A student is preparing to run in a school track competition for the quickest source of energy for student should eat a food that contains a high percentage of

Simple Carbohydrates

Explanation:

Simple carbohydrates are small molecules, so they can be broken down by your body faster, making them an easy and fast source of energy. Simple carbs can be found in glucose and sucrose, so people often feast on fruits, nuts, pasta, and bread-y items before big athletic events, and usually call it "carb-loading".