Final answer:
Protein is the major nutritional contributor to muscle protein synthesis, as it provides the essential amino acids needed for building muscle tissue. Carbohydrates and fats have other primary functions in the body and vitamins do not contribute to muscle synthesis directly.
Step-by-step explanation:
The major nutritional contributor to muscle protein synthesis is c) Protein. Proteins are made up of amino acids, which are the building blocks of muscle tissue. While some amino acids can be synthesized by the body, others, known as essential amino acids, must be obtained from the diet. The process of protein synthesis is critical for tissue formation, production of hormones, and enzymes that are vital for the body's functioning.
Carbohydrates and fats are also necessary macronutrients but they serve different primary functions in the body compared to proteins. Carbohydrates primarily provide energy, and fats are important for various functions including nutrient absorption and energy storage. Vitamins, although crucial for health, are micronutrients required in smaller amounts and do not directly contribute to the building of muscle tissue.