Answer :
The correct answer is:
D. improve the business owners' profit.
Explanation:
A trade union, also known as labor union, is an organization conformed by workers with the purpose of protecting the workers' interests, conditions and benefits. A trade union negotiates with the company on behalf of the workers and helps to settle disputes in the worker-employer relations. It does not take care of the business owners' profit because it focuses only on the workers' pay, conditions and labor journey.