In Response to a Stimulus, Na⁺ and K⁺ Channels Open

Multiple Choice

In response to a stimulus, Na⁺ and K⁺ channels open, allowing for depolarization. The channels respond independently, with

A) both Na⁺ and K⁺ channels opening simultaneously and both remaining active until the end of the action potential.
B) the K⁺ channel opening first, then the Na⁺ channel opening, and only the Na⁺ channel remaining active until the end of the action potential.
C) the Na⁺ channel opening first, then K⁺ channel opening and only the K⁺ channel remaining active until the end of the action potential.
D) both Na⁺ and K⁺ channels opening simultaneously, with the K⁺ channel closing before the Na⁺ channel.
E) the Na⁺ channel opening first, then the K⁺ channel opening, and both remaining active until the end of the action potential.