“In which lesson she doesn’t need to study for a test? ”

[dorax]

“In which lesson she doesn’t need to study for a test? ”
Is the sentence correct or should we use the word subject?

 

[emsr2d2]

It's not correct for more than one reason.

For which subject does she not need to study for the test?

 

[Roman55]

Or, For which subject doesn't she need to study for the test?

 

[Tarheel]

Perhaps:

What subject does she not need to study?

 

[emsr2d2]

Perhaps:

What subject does she not need to study?

That's OK but it loses the specific idea of her studying for a test in that subject.

 

[Tarheel]

A: She doesn't need to study for the test.
B: What subject does she not need to study for?

(Study for the test.
Forget the rest!)