Suppose that a chicken farm uses a nearby stream to dispose of the wastes released by its chickens. These wastes flow downstream into a lake that has become thick with algae and polluted by the minerals in the waste matter. The local office of a nonprofit environmental organization collects enough donations to fund a campaign to stop the farm's pollution. Which of the following types of private solutions to the externality of pollution has occurred in this case?
a. contracts
b. Moral codes and social sanctions
c. Integration of different types of businesses through merger or acquisition
d. Charities

d. Charities

Explanation:

Charity is one  the ways of solving or dealing with externalities that affect a society, without the intervention of the government. This involves the effort of a charitable organization in raising enough money to do something useful for the society to mitigate such externalities affecting it.

As stated in the question above, we can see that the environmental organization is a charitable organization, who have taken it upon itself to advance the course of campaigning against far’s pollution. It is a nonprofit organization that raises money through donations, in order to help finance the campaign. Their main objectives focused on the well-being  the local community.

answer; encouraging the development of innovations by firms attempting to break a monopoly; (creative destruction)