Which of the following statements is CORRECT?

a. Junk bonds typically provide a lower yield to maturity than investment-grade bonds.

b. A debenture is a secured bond that is backed by some or all of the firm's fixed assets.

c. Convertible bonds have lower coupon rates than non-convertible bonds of similar default risk because they offer the possibility of capital gains.

d. Junior debt is debt that has been more recently issued, and in bankruptcy it is paid off after senior debt because the senior debt was issued first.

e. Subordinated debt has less default risk than senior debt.