2009 mc 23

B.
Under wealth max., a person would choose a highest-PV option.
Under utility max., a person will choose a highest-utility option.
They are diff.

C.
they are totally diff.
public good = available for everyone to obtain.
free good = Qs>Qd, P=0

D.
social cost = the effects of results of private actions
externality = diff. between social costs and social benefits AT THE MARGIN

A.
both of them focus on resource distribution.
property right regulates competition behaviour.
They are the closest

easy to confuse with A and D
Be careful