A school that puts the money it earns back into the school.

not-for-profit school.

Explanation:

A for-profit organization can be defined as a type of organization that is created to primarily generate more revenue than its operating costs by providing lawful services to customers. By generating more revenue than operating costs, a for-profit organization is able to make profit.

Some examples of for-profit organizations are privately owned establishments such as hospitals, hotels, restaurants, supermarkets, gas stations, etc.

On the other hand, a not-for-profit organization refers to an organization that is essentially created to provide services without any form of profits or rewards in return. They're usually referred to as a non-governmental organization (NGO) or non-business entity who are only focused on promoting and facilitating social benefits for the people.

Hence, a school that puts the money it earns back into the school is referred to as a not-for-profit school.

answer; is usually (less than) the socially optimal level of consumption;

b is the correct answer