The statement that a fixed coupon bond investor can eliminate reinvestment risk by holding a coupon bond until maturity is incorrect. This is because the investor will receive periodic coupons during the life of the bond. These coupons will need to be reinvested, and there is a risk that the rate at which they can be reinvested will be lower than the original yield of the bond. This is the essence of reinvestment risk. Holding the bond until maturity does not eliminate this risk because the coupons are received and reinvested before maturity. Therefore, the investor is exposed to reinvestment risk until the bond matures.

Choice B is incorrect (as a wrong statement). The yield calculation of a bond does indeed assume that the coupons and the principal can be reinvested at the yield to maturity. This assumption is inherent in the calculation of a bond's yield to maturity, which is why it holds true.

Choice C is incorrect (as a wrong statement). An investor concerned about reinvestment risk would indeed be most worried about a decrease in interest rates. Lower interest rates mean lower returns on reinvested coupons, which increases reinvestment risk.

Choice D is incorrect (as a wrong statement). Zero-coupon bonds do not have any reinvestment risk because they do not pay periodic coupon payments that need to be reinvested. Instead, they are issued at a discount and redeemed at face value upon maturity, eliminating any concern for reinvestment risk.