Which One of the Following Statements Concerning Treasury Bonds Is

Which one of the following statements concerning Treasury bonds is correct?

A) The coupon rate of a TIPS is adjusted periodically in response to changes in the rate of inflation.
B) All Treasury securities are backed by the "full faith and credit" of the Government.
C) Treasury bonds have maturity dates ranging from two to ten years.
D) Interest earned on Treasury bonds is tax- exempt at the federal level.