A silver futures contract requires the seller to deliver 5,000 troy ounces of silver. An investor sells one April silver futures contract at a price of $15 per ounce, posting an $8,400 initial margin. If the required maintenance margin is $6,900, the price per ounce at which the investor would first receive a maintenance margin call is closest to:

a. $13.62.

b. $14.70.

c. $15.30.

d. $16.38.