Richard has $500.00 to invest, but he is willing to borrow money to increase the size of his investment. How much should Richard borrow to construct a portfolio with an expected return of 8% if the risk-free rate is 3% and the expected return of the optimal portfolio is 7%? a. $50.00 b. $100.00 c. $125.00 d. $375.00 e. $625.00