In Regards to Interest Rate Options, Which of the Below

In regards to interest rate options, which of the below statements is TRUE?

A) Interest rate options cannot be written on cash instruments or futures.
B) At one time, there were several exchange-traded option contracts whose underlying instrument was a debt instrument. These contracts are referred to as futures on physicals.
C) In recent years, market participants have made decreasingly greater use of over-the-counter options on Treasury, agency debentures, and mortgage-backed securities.
D) Besides options on fixed-income securities, investors can obtain OTC options on a yield spread.