Which of the following best describes the all-or-none principle of the action potential?

• A. The strength of the action potential is directly proportional to the strength of the stimulus.
• B. The duration of the action potential is directly proportional to the strength of the stimulus.
• C. The magnitude and duration of the action potential are always the same, regardless of the strength of the stimulus.
• D. The magnitude of the action potential decreases as it propagates down the axon.

Answer: (C)