The inactivation rate of voltage-gated Na⁺ and K⁺ channels can regulate the firing frequency of neurons. Which of the following combinations results in the highest firing frequency?

A) Rapid inactivation of both Na⁺ and K⁺ channels
B) Rapid inactivation of Na⁺ channels, slow inactivation of K⁺ channels
C) Slow inactivation of Na⁺ channels, rapid inactivation of K⁺ channels
D) Slow inactivation of both Na⁺ and K⁺ channels