Answer: C. Organizing national conventions and campaign events.
Step-by-step explanation:
The primary elections are held to choose which representative of each political party will participate in the general elections. During the primary elections, each candidate holds national conventions and campaign events during which the political candidate expresses his campaign objectives and plans.
This is why after the primary elections there are no political conventions or campaign events; the candidate that each political party will represent has already been chosen, so the campaign work is focused on defeating the representative of the other political parties.
I hope this information can help you.