B is a weird construction that I would take to mean that someone is required to not work (unless I understood from context that it was a non-native speaker saying that). Or in other words, I take it to mean the same thing as, "She is not allowed to do work." In any case, B isn't something I would use.
They are all fine. Some difference in nuance as others said. Lanthas added an advanced phrase to his reply. In case you're not familiar with it: twiddle one's thumbs 1. 両手の指を組んで親指同士をくるくる回す 2. 〔暇なので〕のんびりしている