Which of the Following Is the Best Description of How

Which of the following is the best description of how actin and myosin work in cooperation to allow muscle contraction?

A) myosin head groups push against actin filaments to lengthen the sarcomere
B) myosin head groups walk along the actin filament to shorten the sarcomere
C) myosin head groups interact with actin only when the sarcomere is fully lengthened
D) all myosin head groups move along the actin filament simultaneously to shorten the sarcomere
E) none of the above