Final answer:
Calcium pumps are responsible for the removal of calcium ions from the myofilaments area, leading to muscle relaxation by allowing tropomyosin to cover the myosin binding sites on actin.
Step-by-step explanation:
The removal of calcium ions from the area of the myofilaments that results in relaxation is mostly accomplished by calcium pumps (answer D). During muscle contraction, calcium ions bind to troponin, which leads to a conformational change in the troponin-tropomyosin complex and exposes the myosin binding sites on actin filaments. As a result, the muscle can contract. However, for relaxation to occur, the calcium ions must be removed. This removal is achieved by calcium pumps, which actively transport calcium ions back into the sarcoplasmic reticulum, away from the myofilaments, allowing tropomyosin to cover the binding sites on actin again, thus leading to muscle relaxation.