The US Chamber of Commerce Represents Thousands of Different Businesses Locally

The U.S. Chamber of Commerce represents thousands of different businesses locally and in Washington. Is it still called an institutional interest, even though it has no single client?

A) Yes, because membership is voluntary.
B) Yes, because it still acts on behalf of other organizations.
C) No, because membership is nonvoluntary.
D) No, because institutional interests represent a single organization.
E) No, because membership is connected to one's occupational background.