A trader buys three August futures contracts on crude oil. Each contract is for the delivery of $1,000$ barrels. The current futures price is $$70$ per barrel, the initial margin is $$4,000$ per contract, and the maintenance margin is $$3,000$ per contract. Under what circumstances could $$3,000$ be withdrawn from the margin account?

A$.$When the trader buys three more futures contracts

B$.$When the futures price increases to $$71$ per barrel

C$.$When the trader sells one of the futures contracts

D$.$When the futures price decreases to $$69$ per barrel