The right answer is C. "Contains the House of Representatives and the Senate". Option A is not correct because, the Legislative Branch has 100 Senators, 435 Representatives, 5 Delegates, and 1 Resident Commissioner. Option B is also incorrect because Representatives have a 2-year term and Senators have 6-year term. Finally, option D is also incorrect because one of the qualifications to run for office in the House of Representatives and Senate is being a citizen of the United States for 7 and 9 years, respectively. It's unnecessary to be natural-born citizen.
