By tradition, when does the presidential campaign begin?
a. in september, following the national convention
b. after a candidate has gained enough electoral votes in the primaries
c. when a candidate is officially nominated at the national convention
d. with the new hampshire primary

The presidential campaign formally opens when a candidate is officially nominated at the National convention. thereafter, the candidate can call out press conferences, conventions to call out his platforms for everyone to know his intentions about the country. The republic allows all legible voters to vote their own cadidate of choice.