Which one of the following is a false statement?

Group of answer choices

a. A corporate callable bond gives its issuer the right to buy back the bonds

b. U.S. treasury debt with a four year maturity is referred to as a treasury note.

c. A corporate convertible bond gives its holder the right to exchange it for a specified number of the company's non-convertible bonds

d. Preferred share owners have preferrence to unpaid dividends over common share owners