You buy one December futures contract when the futures price is $1,010 per unit. Each contract is on 100 units and the initial margin per contract that you provide is $3,000. The maintenance margin per contract is $2,000. During the next day the futures price rises to $1,013 per unit. What is the balance of your margin account at the end of the day? $1,800 a. O b. $3,300 $2,200 C. d. $2,700