The correct answer is C. Competitor.
A rival is someone who competes with another person or group for the same thing, especially in a contest or rivalry.
An enemy is someone who feels or shows hatred or ill-will towards another person or group.
A claimant is a person who makes a claim to something, especially to property or money.
A partner is a person who shares in an activity or business with another person or group.
In the context of the question, the word “rival” is most closely synonymous with the word “competitor.” This is because both words refer to people who are trying to achieve the same thing, such as winning a contest or gaining a position of power.
The word “enemy” is not a good synonym for “rival” because it implies that there is hatred or ill-will between the two people or groups involved. The word “claimant” is not a good synonym for “rival” because it implies that one person or group is trying to take something away from another person or group. The word “partner” is not a good synonym for “rival” because it implies that the two people or groups involved are working together towards a common goal.