Acetylcholine Slows the Heart Rate by

Acetylcholine slows the heart rate by

A) just increasing ion influx, thus increasing the rate of depolarization.
B) just increasing the permeability to Ca²⁺.
C) just increasing the permeability to K⁺.
D) just decreasing the permeability to Ca²⁺.
E) increasing the permeability to K⁺ and decreasing the permeability to Ca²⁺.