How many among the four students A, B, C and D have passed the exam'?

A.The following is a true statement: A and B passed the exam.

B.The following is a false statement: At least one among C and D has passed the exam.

A

The question can be answered by using one of the statements alone, but cannot be answered using the other statement alone.

B

The question can be answered by using either statement alone.

C

The question can be answered by using both statements together, but cannot be answered using either statement alone.

D

The question cannot be answered even by using both statements together.