Which Statement About Ion Movements and Ventricular Muscle Cells Is

Which statement about ion movements and ventricular muscle cells is false?

A) Sustained opening of Ca²⁺ channels is responsible for the extended plateau phase of the action potential.
B) Cardiac muscle is stimulated to contract when Ca²⁺ is available to bind with troponin.
C) For ventricles to fill again, Na⁺ must be removed from the sarcoplasm.
D) Ca²⁺ ions are actively transported out of the sarcoplasm and into the sarcoplasmic reticulum.
E) When Ca²⁺ remains in the sarcoplasm, ventricular muscle cells continue to contract.