Pulse rate peaks during exercise and declines upon stopping

Steps:

• Identify resting baseline: low, steady pulse at start.
• Observe rise: sharp increase during pedaling phase.
• Locate peak: highest pulse rate just before decline.
• Pinpoint stop: onset of decrease marks end of exercise.

Why B is correct:

• Pulse rate begins falling at B, reflecting reduced heart demand post-exercise per cardiovascular physiology.

Why the others are wrong:

• A: Pulse still rising, indicating ongoing pedaling.
• C: Pulse midway in decline, after stopping.
• D: Pulse in full recovery, well after stopping.

Final answer: B