Final answer:
Proprietorships do not use nonprofit accounting guidelines as they are for-profit entities owned by individuals, unlike educational institutions, hospitals, and churches which are nonprofit organizations.
Step-by-step explanation:
The entity that does NOT use nonprofit accounting guidelines among the options provided is c. proprietorships. Educational institutions, hospitals, and churches are all examples of non-profit organizations that must adhere to nonprofit accounting principles because they provide goods and services not to make a profit but to fulfill a service need for the community, like improving education or health. Proprietorships, on the other hand, are forms of business owned by an individual with the intention of making a profit and they do not fall under the non-profit category.