The price of a futures contract to buy $100$ bushels of wheat is $$2\mathrm{.}50$ per bushel. At the end of the day the buying price of wheat rose to $$3$ per bushel:

A$.$ The buyer $($buy position$)$ needs to transfer $$50$ to the seller $($sell position$)$

B$.$ The seller $($sell position$)$ needs to transfer $$50$ to the buyer $($buy position$)$

C$.$ no action is required as in futures contracts all payments are made on the settlement date

D$.$ no action is required since market adjustments occur only when the market price falls below the contract price.