All of these answers are ridiculous, except, of course, for the right answer, which is B. We all know that Juliet was not a submissive daughter, so of course she would defy her family. If she had believed that the friar was going to kill her, she would have never gone to him and asked for his help in the first place. She is also not at all worried about what she will see in the vault. Though she is unhappy about the fact that her parents don't want her to marry Romeo, her main concern in ACT IV is to find a way to be with Romeo.
