Which is not a feature of the contractile cycle in striated muscle?

Which is not a feature of the contractile cycle in striated muscle? a. Binding of Ca2+ to troponin C uncovers the myosin binding sites of actin. b. The power stroke is initiated by the release of Pi from the actin-myosin-ADP-Pi complex. c. The binding of ATP by myosin increases its affinity for actin. d. Rigor mortis results for the inability of actin to release from the actin myosin complex when cells are deficient in ATP.