13. (4 points) An investor set a portfolio using one-unit stock and one-unit option with a strike price of $30 to build a covered call options strategy. When constructing the strategy, the stock price is $20 and the option premium is \$0.5. Assuming that the investor does not sell the stock before the option expires, when the stock price rises to $35 and the risk-free interest rate is not taken into account, the holding period yield of the investor is . (Please keep the answer at most 3 decimal places). 14. (4 points) Suppose Bob need to borrow $1 million in 3 months, but he worries about the interest rate will rise in future. Hence he enters a call option with an agreed interest rate of 4.7%, and sells a put option with agreed interest rate of 4%. Assume the net premium is 0 , his final borrowing rate interval is