Economists Speak of Using Resources to Satisfy Wants,not Needs

Economists speak of using resources to satisfy wants,not needs.They do so because

A) needs are most usefully viewed as wants an individual would give up large amounts of other desirable things to satisfy.
B) only biologists and psychologists are qualified to talk about human needs.
C) there are not enough resources to satisfy all wants of everyone in the world but there are enough to satisfy their needs.
D) people never make choices between their different needs.