The target of medium-and long-term interest rate futures contracts is mainly medium-and long-term government bonds, with a term of more than 1 year. Typical futures in the international market: 2-year, 3-year, 5-year, 10-year treasury bonds futures, German government bonds (2-year euro-—Schatz, 5-year euro-—Bobl, 10-year euro-. Item A belongs to short-term interest rate futures. So the answer to this question is a.