"B" is the only correct answer.
"A" is wrong because whether or not I think she is "bad" has no necessary connection with "having nothing against her". "Bad" is such a vague word. A person can be "bad" in so many different ways.
Likewise, "C" has no relationship with "having nothing against her". For example, I might read in the newspaper about a person who has bad intentions. However, since I don't know her and she is not part of my personal life, why would I have anything against her?