单项选择题

What does, according to the author, economic welfare consist of

A.a general sense of contentment with any individual being part of a group.
B.a basic duality or dichotomy between the amount of pleasures that one individual can experience and discontentment.
C.the act of measuring the amount of gratifications and dissatisfactions with a measure of value.
D.the relentless idea that people have to forfeit in expiation for their pleasures.