In Behavioral Economics, We Assert That: People Sometimes Do Things

In behavioral economics, we assert that: people sometimes do things because they think it is the fair thing to do,

A) even if there is no financial or other material benefit.
B) but actions based on fairness must also be backed by real financial gains or other material or tangible benefit.
C) sometimes expecting nothing in return, but most often expecting real gains also.
D) but only if the net gains exceed the net losses.