Select the most appropriate one-word substitution for the given group of words.
One who rides horses in races

Correct option is A

The correct one-word for the given group of words is (a) jockey.
Jockey refers to a person who rides horses in races.
Meanings of other options:
• Porter: A person employed to carry luggage and other loads.
• Sprinter: An athlete who runs short distances at full speed.
• Athlete: A person who is proficient in sports and other forms of physical exercise.