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\mathrm{.}50.$ Each contract covers $5,000$ bushels of wheat and has an initial

margin requirement of $10\%.$ If the futures price changes to $$3\mathrm{.}30,$ by what $ amount does your margin

account balance change?

a$.$ $$0\mathrm{.}20$

b$.$ $$1,000$

c$.$ $$10,000$

d$.$ $$3,500$