The Chinese Buy a Large Amount of U

The Chinese buy a large amount of U.S. government debt because:

A) they have dollars left over from the sale of their goods to the United States and want to buy something dollar denominated.
B) the U.S. government subsidizes foreign purchases of debt.
C) the rate of return for U.S. government bonds is higher than many other investments.
D) owning U.S. debt is a sign of economic prosperity for the Chinese.