The margin requirement on the S&P 500 futures contract is 16%, and the stock index is currently 2,100. Each contract has a multiplier of $50. a. How much margin must be put up for each contract sold? b. If the futures price falls by 1% to 2,079, what will happen to the margin account of an investor who holds one contract? (Input the amount as a positive value.) c-1. What will be the investor's percentage return based on the amount put up as margin? (Negative value should be indicated by a minus sign. Round your answer to 2 decimal places.) c-2. What would be the current cash balance in the margin account?