Answer:
The correct answer is an incumbent.
Step-by-step explanation:
An incumbent is considered the headline of an office. This is usually related to elections. As an example, when there are elections for President, the incumbent is the person who is in charge of the President's office before the elections take place.
In some cases, there is not an incumbent in the President's office when there is an election, an example of this is when there is a new electoral division. In this case, the office is considered vacant. When there is an election in the United States without the presence of an incumbent, the election is called open seat or open contest.