'to be sighted' is better for at least two reasons.

(1) 'first NOUN to be VERBed' is generally the preferred form in discussing the results of human efforts/actions/interference/perception/etc., while 'first VERBed NOUN' is generally used to indicate inherent qualities of the noun.
for instance, the following sentence is preferred:
henry bishop was the first musician to be knighted by a british monarch. --> knighting is performed by humans
the following is NOT preferred:
henry bishop was the first knighted musician in britain. --> this makes it seem as though being 'knighted' is an inherent quality with which henry bishop was born, or that he acquired it naturally/accidentally in some other way

(2) the word 'sighted' means 'having the sense of sight', so this sentence also contains the amusing alternative interpretation of referring to a pulsar that can actually see.

In D "or rapidly spinning collapsed star" is not a modifier, correct? Therefore does not refer to the "first pulsar" Right?

Ron：you know, i don't really know how you would classify that construction. it probably doesn't count as a modifier, because it doesn't actually modify the noun -- i.e., it doesn't expand upon, restrict, or change the meaning of the noun in any way, as modifiers do.

in any case, regardless of how you may or may not choose to classify it, you should know what this sort of construction (comma + OR + words) does: basically, it provides a definition of the word that comes before it.
e.g.
an own-goal, or goal accidentally scored in one's own net and counting towards the other team's score, is possibly the most embarrassing feat that a soccer player can accomplish.
here, the words following "or" (goal accidentally ... score) are the definition of the term "own-goal".
--
disclaimer:
the above usage is definitely not the only use of "comma + OR"; a much more common use for that construction is as a conventional conjunction, connecting two parallel structures. however, you should know this less common construction, so that you don't immediately mark it as wrong upon seeing it.

'to be sighted' is better for at least two reasons.

(1) 'first NOUN to be VERBed' is generally the preferred form in discussing the results of human efforts/actions/interference/perception/etc., while 'first VERBed NOUN' is generally used to indicate inherent qualities of the noun.
for instance, the following sentence is preferred:
henry bishop was the first musician to be knighted by a british monarch. --> knighting is performed by humans
the following is NOT preferred:
henry bishop was the first knighted musician in britain. --> this makes it seem as though being 'knighted' is an inherent quality with which henry bishop was born, or that he acquired it naturally/accidentally in some other way

(2) the word 'sighted' means 'having the sense of sight', so this sentence also contains the amusing alternative interpretation of referring to a pulsar that can actually see

Choice e：first of all, the word 'discovery' is missing. that's a crucial shift in meaning: it's the discovery, not the pulsar itself, that was 'announced'.
also, the word 'while' - which is sometimes used to indicate contrast - creates a strange ambiguity here: on first reading, it appears to suggest that the announcement (which took place in '68) happened during the summer of '67; this is the usual sense of 'while' occurring in this place in a sentence. (normally, if used to mark contrast, 'while' appears in front of a sentence.)

if 'while' is used for contrast, then it indicates that contrast IN ADDITION TO simultaneity. it's specifically used to describe two contrasting things that are simultaneously true.

yes that's awfully specific, but we can afford that kind of specificity because there are plenty of other contrast transitions (whereas, but, although, even though, yet, etc.) to describe situations that don't fit the 'simultaneity' criterion.

A的it指代了star被announced had not 错误
B是这个student not announced错误 although放错地方了
C 是 discovery被observed不对
E 这个star 没被announced

AC的had 就错了1968年的发现是发生在1967年后面的
C的话就是转折放错了地方，语义不对了
E while 感觉语序错误了

a选项是这个星星被announced，应该是discovery被announced。另一个排除a的点是，to be sighted是修饰的star，按照句子结构分析，was。。。by。。。缺少了observed，正确应该是was observed by...

应该是the discovery was not announced
对比选项

e
The first sighted pulsar 错

observe pulsar, announce discovery

关于had not been
【过去完成时有标志两个发生在过去的动作 或者两个时间点的顺序的意思】如果句子中有before、after这类能表示动作前后顺序的词，就没有必要一定要使用复杂的过去完成式了，不要轻易淘汰那些只使用一般过去时的选项。
EG: laura LOCKED the deadbolt BEFORE she LEFT for work.

关于to be sighted
(1) 'first NOUN to be VERBed' is generally the preferred form in discussing the results of human efforts/actions/interference/perception/etc., while 'first VERBed NOUN' is generally used to indicate inherent qualities of the noun.
for instance, the following sentence is preferred:
henry bishop was the first musician to be knighted by a british monarch. --> knighting is performed by humans

The first pulsar, or rapidly spinning collapsed star,( to be sighted) was

announce，宣布，宣布发现了星星这件事情（the doscovery），而不是宣布这个星星。

while还有“与此同时”的意思，可能会造成E的意思有歧义。另外。discovery才是可以被announced的对象。

时刻要关注逻辑论元

first pulsar, or rapidly spinning collapsed star, to be sighted was observed 这里sight 和 observed 没有意思重复吗

A star was in thesummer 错误 it指代star，star不能被announce
B 核心词替换，学生不能被announce
C 被观测到的应该是star不是发现本身
E star被announc错误

A： although 让步状语从句里提出主干为：pulsar [to be sighted] was in the summer by JB。 这里不定式to be sighted是作为定语修饰pulsar， 所以这句话实际是 pulsar was in summer显然不对。
B：Although not announced ，主句主语是JB，而这里被announced的对象明显是星星不是人，杀掉
C：错误同B，让步状语的逻辑主语是discovery，错， 杀掉
E：主句pulsar was not announced，星星不是被announce的对象，应该是discovery， 杀掉。另外while用在后面链接这俩的转折关系也有点奇怪，感觉好像顺序错了

CD 二选一错了 在 announce 的时态上 没考虑 好 宣布 是 一个时刻........

a using part perfect tense is incorrect, as 1968 is later than 1967