What occurs at a national convention held by major political parties?

The national convention held by major political parties is a significant event where delegates from various states gather to perform key functions that shape the party's direction and strategy for the upcoming elections. The primary focus of these conventions is to decide on candidate nominations, where delegates formally nominate individuals to run for President and Vice President. Additionally, these conventions serve to create and outline the party platform, which reflects the party's principles, priorities, and policy goals.

This process is crucial because it not only unifies the party behind its candidates but also communicates its core messages and values to voters. By adopting a party platform, the convention establishes the guiding principles that candidates and party members will promote during the election campaign. The deliberative nature of the convention allows for input and debate on various issues, ultimately leading to a cohesive strategy for elections.

In contrast, the other options do not accurately represent the primary functions of a national convention. Local officials are elected through different electoral processes rather than at national conventions. Approval of state policies often occurs within state legislatures or local governance structures, and annual financial audits pertain to financial oversight and reporting, which are not central activities at a national convention.