Which of the following is/are correct regarding interest rates? Choose all the correct answers.

a. Borrowers preference for long duration and lenders preference for short duration causes the term premium to be positive. b. Zero-coupon bonds are less sensitive to interest rate changes compared to coupon bonds with the same time to maturity. c. The yield curve is usually flat. d. Bonds with greater default risk typically trade at lower yield-to-maturities. e. An inverted yield curve serves as a negative indicator for the future state of the economy.