Which of the Following Is the First Step in the Sliding

Which of the following is the first step in the sliding mechanism of muscle contraction

A) The myosin heads of the thick filaments bind to active sites on the thin filaments.
B) Myosin heads pivot toward the M line when cross-bridge binding occurs.
C) Thin filaments are pulled toward the center of the sarcomere.
D) The cross-bridges detach and return to their original positions.
E) A carbohydrate molecule is broken down to produce energy.