Which One of the Statements About Margin Requirements on Option

Which one of the statements about margin requirements on option positions is not correct?

A) The margin required will be higher if the option is in the money.
B) If the required margin exceeds the posted margin the option writer will receive a margin call.
C) A buyer of a put or call option does not have to post margin.
D) Even if the writer of a call option owns the stock the writer will have to meet the margin requirement in cash.