Actually, it seems like you have found an error here! The original sentence for this one is written as としたら, but とすると is accepted as an alternative answer. In this case, although it is grammatically correct, とすると would be unnatural, as the result is far more definite with とすると, so using it with an assumption about the future, which is not definite, would not be appropriate.
I will change this so that it is not accepted as a correct alternative.
As for why としても is not accepted, that is because there is not contradictory logic between the (A) and (B) part of the sentence. としても usually indicates that there is a contradiction. In the first half, the person assumes they didn’t study, and in the second half the result would be typical of someone that did not study. However, if we changed the first half to もし勉強したとしても, then としても would be acceptable, because the contradiction of studying, but having a bad result anyway would be in place.