where / in which

[Trex]

PTSD sufferers may experience flashbacks ---- they feel they are going through the ordeal.

A) in which
B) in whose
C) where
D) how
E) what

I am stuck between A and C. What is your opinion?

[MikeNewYork]

PTSD sufferers may experience flashbacks ---- they feel they are going through the ordeal.

A) in which
B) in whose
C) where
D) how
E) what

I am stuck between A and C. What is your opinion?

A is better. "Where" is an adverb of place and really doesn't fit here.

[BobK]

PTSD sufferers may experience flashbacks ---- they feel they are going through the ordeal.

A) in which
B) in whose
C) where
D) how
E) what

I am stuck between A and C. What is your opinion?

That's a good place to be! B, D and E are just wrong. As Mike said, 'in which' is best, but I've heard both 'where' and 'when' in this context (in informal speech).

b