For Matthew, the Marginal Utility of the Tenth Coffee in a Day

For Matthew, the marginal utility of the tenth coffee in a day is zero.

A) This implies that Matthew's demand curve for coffees per day will become upward- sloping at ten coffees per day.
B) This suggests that Matthew must maximise utility by consuming ten coffees per day.
C) This is impossible because each additional unit of consumption of any good must provide positive marginal utility.
D) This suggests that Matthew must maximise utility by consuming zero cups of coffee per day.
E) This implies that, at a zero price, Matthew's demand curve will intersect the quantity axis at ten.