Thin filaments in skeletal muscles are mainly composed of which of the following?

Thin filaments are polymers made up of two chains of actin that forms a long double helix. Tropomyosin molecules are long filaments located in the groove between the two chains in the actin. Each thin filament contains 300-400 actin molecules and 40-60 tropomyosin molecules. Troponin molecules are small globular units located at intervals along the tropomyosin molecules. There are 3 troponin subunits. Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin. Troponin C contains the binding sites for the Ca2+ that helps to initiate contraction. Thick filaments have twice the diameter of thin filaments and are made up of myosin. Ref: Ganong's Review of Medical Physiology, 24e, chapter 5