Which of the following is considered a basic class of nutrients that includes starch, sugar, and dietary fiber?

Carbohydrates are a fundamental class of nutrients that serve as a primary energy source for the body. This category encompasses various forms of sugars, starches, and dietary fibers.

When it comes to sugars, they can be simple (like glucose or sucrose) or complex (like those found in starch). Starch is a polysaccharide and serves as the storage form of energy in plants, while dietary fiber, although not digestible, plays a crucial role in maintaining gut health and regulating blood sugar levels.

In contrast, vitamins, proteins, and minerals represent other essential nutrients with different functions. Vitamins are organic compounds that are vital for normal growth and metabolism but are not primarily energy sources. Proteins are made of amino acids and are essential for building and repairing tissues, while minerals are inorganic elements that support various physiological processes but do not provide calories as carbohydrates do.

Thus, the classification of starch, sugar, and dietary fiber clearly identifies them as carbohydrates, making this option the correct choice.