Which One of the Following Is True About Bond Income

Which one of the following is true about bond income funds?

A) They invest in bonds that provide steady coupon cash flows and are quite varied in their risk level.
B) They could be made up of a portfolio of entirely corporate bonds (risky) or a portfolio of entirely Treasury issues (no default risk) or of mortgage-backed securities.
C) They may be exposed not only to default risk, but also to interest rate risk.
D) They are attractive to investors close to retirement age as the income stream of fund's instruments provides them with necessary income.
E) All of the above are true.