An Increase in Heart Rate Is Accompanied by

An increase in heart rate is accompanied by

A) an increase in L-type Ca²⁺ channel activity.
B) an increase in K⁺ flux through voltage-gated K⁺ channels.
C) an increase in the passive movement of Na⁺ into cells of the SA node.
D) an increase in the passive movement of K⁺ out of cells of the SA node.
E) a combined increase in passive movement of Na⁺ and K⁺ out of the cells of the SA node.