Which of the following statements is INCORRECT?

a. Duration changes only because of time passage.

b. Duration overestimates the decline in price for an increase in interest rates.

c. Convexity adjustment improves duration price approximation.

d. Duration of a zero-coupon bond is the same as time to maturity.

e. Other things being the same, lower-coupon bonds have more curvature in the price-yield curve.