Final answer:
The contractile ring contains actin, which is involved in the cell division process by helping to form the ring that pinches the cell into two separate cells.
Step-by-step explanation:
The contractile ring is a structure that forms during the process of cytokinesis in cell division. It is made of filaments that are responsible for pinching the cell membrane to eventually separate the cell into two daughter cells. Among the given options, the component of the contractile ring is actin. Actin filaments, along with myosin, are involved in muscle contraction as well, but in the context of the contractile ring, they play a crucial role in cell division.