Correct Option: C

ATPase enzyme is located in the myosin cross bridge heads. Actin forms the light or I- Band. Actin slides over myosin during contraction. Troponin protein is involved in establishing connection with myosin cross bridges. Actin is not involved in muscle contraction. It is also an ATPase (an enzyme) which is activated by Ca²⁺ and Mg²⁺ ions. Hence, ATPase enzyme is located in myosin.