Which option lists the four broad classes of performance-enhancing substances?

• A. Stimulants, diuretics, vitamins, minerals
• B. Carbohydrate supplements, amino acids, fluids, electrolytes
• C. Anabolic agents, peptide hormones, beta-2 agonists, masking agents
• D. Painkillers, antibiotics, antivirals, vaccines

Answer: (C)

In sports, performance-enhancing substances are commonly grouped into four broad classes that cover the main ways drugs can boost performance. Anabolic agents drive muscle growth and strength by increasing protein synthesis. Peptide hormones like growth hormone or erythropoietin stimulate systemic effects such as tissue growth or increased red blood cell production, which can enhance endurance and recovery. Beta-2 agonists can have anabolic and bronchodilating effects, assisting performance in some contexts. Masking agents are substances used to conceal the use of banned drugs, helping athletes evade detection.

This set matches those four categories, making it the best choice. The other options mix vitamins or minerals, general supplements, or unrelated medications with no clear, standard four-class structure for performance-enhancing substances.