Which of the following is false?

a. We can be sure that people with more income get less marginal utility from their consumption of a good than those with less income.
b. We can be sure that people with less income get less marginal utility from their consumption of a good than those with more income.
c. We can be sure that those who receive greater marginal utility from consumption of a particular unit of an item receive greater total utility from consumption of that item.
d. All of the above are false.

d