In which lesson she doesnt need to study for a test?
Is the sentence correct or should we use the word subject?
In which lesson she doesnt need to study for a test?
Is the sentence correct or should we use the word subject?
It's not correct for more than one reason.
For which subject does she not need to study for the test?
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
Or, For which subject doesn't she need to study for the test?
I am not a teacher
Perhaps:
What subject does she not need to study?
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!)