My parents are going to China . . . . . . . . a holiday . . . . . . . . September.

A. in, at

B. for, in

C. so, that

D. for, during

Answer: Option B

Solution(By Examveda Team)

The first blank will take 'for' as 'for' indicates purpose. Here, the purpose is holidaying.
The second blank will take 'in' as 'in' is used for months, years, centuries and long periods.