You purchase 180 shares for $70 a share ($12,600), and after a year the price fails to $60. Calculate the percentage return on your investment if you bought the stock on margin and the margin requirement was (ignore commissions, dividends, and Interest expense) a. 20 percent. Use a minus sign to enter the amount as a negative value. Round your answer to one decimal place % b. 45 percent. Use a minus sign to enter the amount as a negative value. Round your answer to ore decimal place, 96 C. 85 percent. Use a minus sign to enter the amount as a negative value. Round your answer to one decimal place