10. suppose you walk into the capitol in washington and ask to interview the most prominent person in the entire congress. if they accept, you'll get an appointment with the a. chair of the house appropriations committee. b. president pro tempore of the senate. c. vice president of the united states. d. speaker of the house.

The answer is D) Speaker of the House.
The Speaker of the House represents the entire House of Representatives. This is the most prominent role in the entire Congress. The argument could be made that the Senate Majority Leader is the most prominent member, but it would be difficult to justify, given the Speaker's influence over the creation of laws in the House, and besides, it is not an option.