Which statement most accurately summarizes the primary biological roles of chloride, magnesium, and sulfur?

Chloride functions chiefly as an extracellular electrolyte and component of stomach acid; magnesium is a widespread enzyme cofactor and electrolyte needed for nerve, muscle, and heart function; sulfur is part of certain amino acids and some B vitamins that stabilize protein structure.

Chloride is mainly stored intracellularly for energy production while magnesium forms thyroid hormones and sulfur is the principal ion controlling blood pH.

Magnesium is only important during exercise for ATP breakdown, chloride acts only as a dietary preservative, and sulfur is required exclusively for vitamin C synthesis.

All three minerals primarily function as energy substrates for the Krebs cycle, with sulfur acting as the rate-limiting nutrient and magnesium and chloride as coenzymes for ATP synthesis.