I'd say trustworthiness, your friend is trusting you with keeping a secret that he or she will only share with you. I hope this helps :)
The answer B makes the most sense.
Sherbet is often served as a palate cleanser between courses
(C) sherbet
That's so easy! It's HIV! HIV is pretty much like AIDS which is a virus. It's the stage before you get AIDS and you're guaranteed to die.
Hope this helps!