CD可以先排除因为attempt和try 重复
然后B try that 错了
A trying是想用动名词 但是没有attempt好 A的it是指代什么

The -ing form of a verb can be used as a noun (e.g., running is her favorite sport), but it is often awkward, particularly when used with a possessive, as in this case. Substituting the noun attempt for the gerund trying eliminates the problem. While chemical that is irritating it and chemical irritating it are both grammatically correct and could be appropriate in some usages, they are excessively wordy for this context.

A trying没有 attempt简洁，that is irritating it没有the chemical irritant简洁
还原后trying to metabolize the chemical that is irritating it, or (to)render the chemical harmless that is irritating it.
B 没有try that,it后面应用单数
C attempt to try 重复
D attempt to try and metabolize 重复，不平行

A中it指代不明，CD中try和attempt重复，B中try that错误
E还原为attempt to metabolize, or render the chemical irritant harmless
render为＂使得＂的意思(后接受词+受词补语 )
chemical irritant->指dioxin(受词, O.)
harmless->受词补语(O.C.)
受词补语(O.C.)较受词(O.)短时,老美会将受词补语移到受词前,让句子结构呈现头轻脚重的形式