Human body requires calcium and sodium for the contraction of muscles.

Explanation:
1. Calcium:
- Calcium is an essential mineral required by the human body for various physiological functions, including muscle contraction.
- During muscle contraction, calcium ions play a crucial role in initiating and regulating the process.
- When a muscle is stimulated to contract, a signal is sent from the brain to the muscle fibers. This signal triggers the release of calcium ions from the sarcoplasmic reticulum, a specialized structure within muscle cells.
- The released calcium ions bind to a protein called troponin, which is part of the muscle fiber structure. This binding causes a conformational change in troponin, which in turn allows another protein called myosin to bind to actin.
- The binding of myosin to actin leads to the sliding of actin filaments over myosin filaments, resulting in muscle contraction.
- Therefore, calcium is essential for the initiation and regulation of muscle contraction.

2. Sodium:
- Sodium is another mineral required by the human body for muscle contraction.
- During muscle contraction, an electrical signal is sent from the brain to the muscle fibers. This signal, known as an action potential, is generated by the movement of ions across the cell membrane.
- Sodium ions play a crucial role in the generation and propagation of action potentials. They enter the muscle cell through specialized channels in the cell membrane when the membrane is depolarized.
- The influx of sodium ions leads to a rapid change in the electrical potential across the cell membrane, triggering the contraction of the muscle fiber.
- Therefore, sodium is necessary for the generation and propagation of action potentials, which are essential for muscle contraction.

Conclusion:
Both calcium and sodium are required by the human body for muscle contraction. Calcium is involved in the initiation and regulation of muscle contraction, while sodium is necessary for the generation and propagation of action potentials. Therefore, option C, which includes calcium and sodium, is the correct answer.