Troponin assists in controlling the interaction between myosin heads and thin filaments by ________.

A) forming a long chain that covers the active sites of thin filaments
B) storing calcium ions in the troponin-tropomyosin complex
C) binding to myosin heads, which allows tropomyosin to pivot, thereby exposing the active sites
D) assisting in the formation of the myofilaments
E) binding calcium ions to produce a change in the orientation of the troponin-tropomyosin complex