Step 1: Think about what athletes need during a race.
While running or playing a match, an athlete's muscles burn through energy fast. The body must supply that energy without delay, so the fuel used has to be one that breaks down quickly.
Step 2: Identify the fast fuel among the choices.
Carbohydrates are stored as glycogen in muscles and the liver. Glycogen converts into glucose within moments, and muscles use that glucose right away. This is why athletes often eat carbohydrate rich meals like pasta or bananas before an event.
Step 3: Explain why the others fall short.
Fat holds plenty of energy but needs more oxygen and more time to break down, so it suits slow, long duration effort rather than a quick burst. Vitamins carry no calories at all. Protein is meant for repairing muscle fibers, not for supplying quick fuel.
Step 4: State the conclusion.
Since carbohydrate breaks down fastest into usable glucose, it is what gives athletes their quick energy.
The correct answer is Carbohydrate.