Which of the following is a reason why zero-coupon bonds are the best way for high-income taxpayers to extract maximum value from tax-exempt state and local government bonds? a. Zero-coupon bonds include more transaction fees. b. The investments pay interest continually. c. Zero-coupon bonds are high-risk, high-reward bonds. d. Zero-coupon bonds allow the investor to make additional tax-exempt investments. e. The interest earned on the accumulated principal and interest is not tax-exempt