Obeying :

Answer: Option C

Following: coming after or as a result of.
Refusing: indicate or show that one is not willing to do something.
Contradicting: deny the truth of (a statement) by asserting the opposite.
Protesting: a statement or action expressing disapproval of or objection to something.
Ordering: let, enjoin, license, order, send an order, ordain.
Obeying: acting according to what one has been asked

So antonym of obeying is refusing.