看到一个解释：better control of other infections such as---后面举例的就应该是control的手段 如果是better control of such infections as--后面举例的就应该是infection，非划线部分的两个例子是感染，所以A的结构是肯定不对的

what是确定的（有且仅有的）一件事，而something强调的是只要是一件事即可；A中the other错误

重点分析A和C选项。A使用what而C使用something，两者在语法上没错，但使用what强调的是某个特定的事，something没有强调某个特定的事；此外，A选项的the other使用错误，正确的结构应该是one ... the other ...。此外，the other 和 such as是不兼容的，正确的表达应该是of other infections such as ...

- Minor problem is "what they had not..." vs. "something they had not..." The "what" construction is awfully strong, suggesting that this was THE ONE THING they hadn't thought possible.
* As an analogy, compare the meanings of "I want to do what I love for a living" and "I want to do something I love for a living." The first suggests that the speaker has one particular field in mind; the second doesn't.

* THE is also incompatible with "such as":
- Correct: I never read this book, but I read the other books on the shelf.
- Correct: I never read this book, but I read other books on the shelf, such as "Right Hand, Left Hand" and "The Rise and Fall of the Third Reich."
- Incorrect: I never read this book, but I read the other books on the shelf, such as "Right Hand, Left Hand" and "The Rise and Fall of the Third Reich."

最终A和C纠结。ron said A错在 1）the other infections such as ..这里the太局限了，限定了一个every single one of the other infection。 2 THE 与 such as不兼容 incompatible。3）错在what引导的从句和其他选项something后定语从句的区别是，
ron说a的主要问题是"THE other infections.的the. "The"太definitive，涵义是 "every single one of the other infections." 。而且THE is also incompatible with "such as”。