Which of the following is true?

Which of the following is true?
A) The amount of satisfaction derived from the consumption of each successive unit of a given good is greater than the amount of satisfaction derived from the consumption of a previous unit
B) The amount of satisfaction derived from the consumption of each successive unit of a given good is less than the amount of satisfaction derived from the consumption of a previous unit
C) Total utility and marginal utility must eventually be equal for a rational consumer
D) Consumption of successive amounts of one good yields constant amounts of utility