4. Zack Wheat has just bought four September 5,000-bushel corn futures contracts at $4.95 per bushel. The initial margin requirement is 4%. a) How many dollars in initial margin must Zack put up? b) If the September price of corn rises to $5.36, how much equity is in Zack's commodity account? Compute $ and % profit or loss. c) If the September price of corn falls to $4.50, how much equity is in Zack's commodity account? Compute $ and % profit or loss.