You are a wheat farmer that has entered into 10 short futures contracts with a delivery date 3 months from today. The futures price is $3.50. Each contract covers 5,000 bushels of wheat and has an initial margin requirement of 10%. If the futures price changes to $3.30, by what $ amount does your margin account balance change?

a. $0.20

b. $1,000

c. $10,000

d. $3,500