A Trust is a group of companies with significant market power working as a corporation or a group of corporations cooperating with each other in several ways.
The correct answer is alternative D) "a large company or combined businesses that control a specific market "
This alternative clearly describes the cooperation of companies in a specific market.
One company, even if it's the result of a merger doesn't count as a trust.
They don't need to be determined by their location, so alternative B is out of the question.
Buying another business doesn't make you a trust.
