This question asks you to choose the answer choice which "follows logically" from the statements. This is just a fancy way of asking you to find the conclusion which fits with the premises provided. Here's a breakdown:
Premise: If SC quorum - - - then GA at 6. Premise: If AC quorum - - - then GA at 7. Conclusion: ??
Answer Choices: (A) is incorrect. This answer choice assumes that either AC or SC must have a quorum. It's possible that the both don't have a quorum.
(B) is incorrect. Again, this is assuming that either AC or SC must have a quorum. There is nothing in the premises to support this.
(C) is incorrect. This reverses premise 1 which we can't do (with an if/then statement, you can't just reverse the then/if to get a new conclusion). There could be many other reasons for the GA to begin at 6 that we just don't know about.
(D) is incorrect. This is just the opposite of answer choice A and is likewise wrong.
(E) is correct. The GA is a single event, and therefore cannot begin at both 6 and 7 on the same night. If both committees were to have a quorum, it would have to. Therefore, we know that both committees can NOT have a quorum.