Final answer:
The muscle component primarily comprising actin, tropomyosin, and troponin is the thin myofilaments within the myofibrils of muscle fibers.
Step-by-step explanation:
The muscle component that is primarily comprised of actin, tropomyosin, and troponin is known as myofilaments, specifically the thin filaments. Myofibrils are larger structures that contain the myofilaments arranged into repeating units called sarcomeres, which are the smallest contractile units of a muscle. Thick filaments are primarily composed of the protein myosin, whereas thin filaments are primarily composed of actin, along with tropomyosin and troponin which serve as regulatory proteins.