Which of the Below Statements Is TRUE

Which of the below statements is TRUE?

A) Futures contracts are marked to market at the end of most trading days.
B) A forward contract may or may not be marked to market, depending on the wishes of the two parties.
C) For a forward contract that is not marked to market, there are interim cash flow effects because no additional margin is required.
D) The parties in a forward contract are not exposed to credit risk because either party may not default on the obligation.