Hi teachers,
I am sure the right one is 'a'? My question is why here the verb 'did' only affects 'say' and not 'laughed'?
a) What did she say when she laughed?
b) What did she say when she laugh?

Because we say, 'What did he do and say later? / What do you like and dislike about the film?'

What kind of sentence, grammatically speaking, is 'a' besides being a question?

Thanks in advance.