正确答案：BC
解析：
Freshman are no longer "coddled in an..." Instead they are in the "treacherous waters...anonymity." Therefore, no one is there to help them. It is up to them, or incumbent upon them. (C) is a synonym.
(D) means removing the burden of responsibility, which is the opposite of the context. (A) suggest a sense of guilt that is not supported by the context.
(F) could work, but it has no similar answer choice.