Roman citizens had the responsibility to pay taxes and serve in the military. This was a fundamental expectation of citizenship in ancient Rome.
The other options mentioned are not responsibilities of Roman citizens: citizens did not have the authority to veto the actions of tribunes (that was the role of the tribunes themselves), women did not have the right to vote, and while citizens did participate in electing certain officials, including tribunes, they did not directly elect Roman senators as the Senate was primarily filled by appointment or through other means rather than direct election.