Answer:
C. The cross bridge would move the actin filaments towards the center of the myosin.
Explanation:
Contraction of a muscle is a process in which the sarcomere shortens after being adequately stimulated.
Two main proteins involved in this process are actin and myosin. In a state of relaxation, they are not binded, because their binding places are blocked. After the stimulation, these binding places are free, so the two proteins bind and form the cross bridge.
Now, actin filaments slide from one to another binding places along the length of a myosin fibers, like a paddle of the boat across the water.
Note that during this process actin and myosin don't change their length; the sarcomere shortens because the actin filaments slide towards the center of the myosin fibers.
