Final answer:
You are most likely participating in a primary election to choose the nominee for the Republican party.
Step-by-step explanation:
In this scenario, you are most likely participating in a primary election.
A primary election is when party members vote for their party's nominee for an office, such as president.
On your ballot, you have candidates from both the Democratic and Republican parties, which indicates that you are voting in a primary election to choose the nominee for the Republican party.