Se Suppose that you enter into a short futures contract July silver for $5.20 per ounce on the New York Commodity Exchange. The size of the contract is 5,000 ounces. The initial margin is $4,000, and the maintenance margin is $3,000. (a) What change in the futures price will lead to a margin call? (10 points) (b) Under what circumstances could $1,200 be withdrawn from the margin account? (10 points)