If People Decide There Is a Problem Worth Solving That

If people decide there is a problem worth solving that requires the creation of a public good, government involvement is necessary because

A) majority factions will try to ensure that the good works only for themselves.
B) it is difficult for individuals to provide common resources on their own.
C) of positive externalities that make the good otherwise undesirable.
D) without it, citizens would be able to sue the government in federal court.