Refer to the figure below. Total utility increases with each additional pizza up to the _ and then declines, but marginal utility _ with each additional pizza consumed.

Refer to the figure below. Total utility increases with each additional pizza up to the _ and then declines, but marginal utility _ with each additional pizza consumed.
A.6th pizza; increases
B.6th pizza; decreases
C.5th pizza; stays the same
D.7th pizza; increases
正确答案：6th pizza; decreases