Comparing Excitation-Contraction Coupling in Cardiac Muscle with That in Skeletal

Comparing excitation-contraction coupling in cardiac muscle with that in skeletal muscle:

A) Extracellular calcium plays a major role in cardiac but not skeletal muscle
B) The stimulus for calcium release from the sarcoplasmic reticulum is the same in both muscles
C) Troponin sites are always saturated immediately after calcium release in both muscles
D) There is no net change in total intracellular calcium concentration in either muscle
E) Both extracellular calcium plays a major role in cardiac but not skeletal muscle and the stimulus for calcium release from the sarcoplasmic reticulum is the same in both muscles are correct