PREP 33

33. Many teenagers undergo stress, but results of a recent study indicate that the patterns of stress that girls experience are more likely to result in depression than are those that boys experience.  A

A are those that boys experience

B what boys experience

C boys’ experience would

D boys’ stress patterns do

E stress patterns of boys

A: correct，than前面用名词，所以助动词补出；those指代patterns

B: 比较对象不对等

请问B的what指代什么，为什么不对等？