Final answer:
The term that refers to areas where imperial powers had exclusive trading rights in the 18th and 19th centuries is concessions.
Step-by-step explanation:
The term that refers to areas where imperial powers had exclusive trading rights in the 18th and 19th centuries is D) Concessions.
A concession is a right granted by a government to an individual or a company to carry out specific activities, such as trading, in a designated area. In the context of imperialism, concessions were often granted by imperial powers to foreign companies, giving them exclusive trading rights in a particular region.