Which ion gradient across the axon membrane is primarily responsible for generating the resting membrane potential?
AHigh Na⁺ inside, low Na⁺ outside
BHigh K⁺ inside, low K⁺ outside (maintained by Na⁺/K⁺ ATPase)
CHigh Ca²⁺ inside, low Ca²⁺ outside
DHigh Cl⁻ inside, low Cl⁻ outside