What Action Is Most Responsible for the Resting Membrane Potential

Multiple Choice

What action is most responsible for the resting membrane potential in cardiac muscle cells?

A) Movement of K⁺ through voltage-gated K⁺ channels
B) Movement of Na⁺ through open Na⁺ channels
C) Movement of Ca²⁺ through voltage-gated Ca²⁺ channels.
D) Closing of Na⁺ and K⁺ voltage-gated channels