Answer:
The first and third
Step-by-step explanation:
Since 1972, the delegates have been mostly selected in presidential primaries state by state. This allows the nominees to be decided before the convention opens. In the 1976 GOP race, Ronald Reagan did well in the primaries but had clearly lost to incumbent Gerald Ford when the convention opened. Other delegates to these conventions include political party members who are seated automatically, and are called "unpledged delegates" because they can choose for themselves for which candidate they vote.
Generally, use of "presidential campaign nominating convention" refers to the two major parties' quadrennial events: the Democratic and Republican National Conventions. Some minor parties also select their nominees by convention, including the Green Party, the Socialist Party USA, the Libertarian Party, the Constitution Party, and the Reform Party USA.