No, a preposition is often used to describe where usually following a noun, such as in, on, with, by, and etc.
"But" is a coordinating conjecture. Hope this helps.!
Underestimating people is a huge mistake. Often, those who appear to be innocent are everything but.
The answer is B.
Reason: disobedience means not obeying, and if you do it civilly, then you are not obeying but in a way that is peaceful and respectful.