Congress passed a controversial bill regulating firearms. The bill's constitutionality was questioned, and the bill was challenged in court. Ultimately, the Supreme Court upheld the provision. A sunset provision in the original bill meant that Congress had to reauthorize the bill every two years. The first time the bill was up for reauthorization, the President vetoed it. His veto message asserted that the measure was unconstitutional. Is the President's action constitutional?
a) Yes, as the President has the authority to veto bills based on constitutional concerns
b) No, as the Supreme Court has already upheld the constitutionality of the provision
c) Yes, but only if the President provides detailed reasoning for the constitutional concerns
d) No, as the President's veto power does not extend to constitutional questions