(A) Lactose
(B) Proteins
(C) Vitamins
(D) Glucose
🧠 Explanation:
- The brain relies heavily on glucose as its primary source of energy.
- Glucose is a simple sugar that fuels brain cells for proper functioning.
- Unlike muscles, the brain cannot store energy, so it needs a constant glucose supply.
- Proteins, vitamins, and lactose are important, but not the brain’s main energy fuel.