In this task, you are given a question containing a blank (_) and two options. You should pick the best option to answer the question. Please answer with "A" or "B".

[EX Q]: Though they both owned guitars Rebecca actually played while Amy didn't because _ knew how to read music. (A) Rebecca (B) Amy
[EX A]: A

[EX Q]: Rachel played in the swimming pool while Jessica jumped in the muddy puddle. _ was still clean when they returned home. (A) Rachel (B) Jessica
[EX A]: A

[EX Q]: The students used the cards instead of the books to improve their memory of the subject because the _ were already studied. (A) cards (B) books
[EX A]:
B