How long must candidates for senator have been citizens of the United States?

A. at least two years

B. at least four years

C. at least nine years

D. at least six years

answer is c. nine years

Candidates for senator have to had been citizens of the united states at least for 9 years.

Explanation:

According to the constitutional qualifications for senator from the United States of America senate, every senator candidate should have certain qualifications. One of them is that every senator candidate should have been a citizen of the United States of America for at least 9 years before its candidacy. Because it is seen as an act of compromise to the nation and also because it is an equal treatment measure. Securing equality and preventing discrimination.