U. S. Treasury securities face several risks to varying degrees. Generally speaking, rank the following risks that an investor in a 5 percent coupon, 25-year, off-the-run U. S. Treasury bond, issued after 1984, would face. Order them from left to right with the least likely risk first through the most likely risk faced by the investor last. 1=liquidity risk. 2=prepayment risk. 3=default risk. 4=interest rate risk.（）
A. 1, 2, 3, 4.
B. 2, 3, 1, 4.
C. 4, 3, 1, 2.
