You have been hired to value a private firm with $5 million in annual revenues. To estimate the firm's cost of cap- ital, you must decide on a risk-free rate of return. As shown in the Federal Reserve's publication H.15, available on the Internet, many kinds of U.S. Treasury securities exist that are free from default risk. Draft the language in your valuation report for this project describing which Treasury security you have chosen for your risk-free rate, and explain your reasoning for choosing that security instead of any other Treasury security.