Final answer:
Weightlifting is not a cardiorespiratory endurance activity, as it focuses on muscle strength rather than cardiovascular health.
Step-by-step explanation:
The activity that is not a cardiorespiratory endurance activity is C) Weightlifting. Cardiorespiratory endurance activities are typically aerobic exercises. These include actions like running, cycling, and swimming, which improve cardiovascular health and increase muscular endurance due to their moderate intensity and extended duration. On the other hand, weightlifting is considered an anaerobic exercise that focuses on increasing muscle strength and often involves short bursts of activity rather than continuous movement, which is the hallmark of cardiorespiratory activities.