Suppose Two Neighbors Share a Park

Multiple Choice

Suppose two neighbors share a park.One neighbor,Al,leaves trash in the park.This bothers the other neighbor,Bert.According to Coase's Theorem,the optimal level of trash in the park can be achieved if

A) someone is assigned property rights to the park.
B) government limits the use of the park.
C) nobody catches Al leaving the trash.
D) Bert moves.