The main active constituent of tea and coffee is A. nicotine B. chlorophyll C. caffeine D. aspirin

The main active constituent of tea and coffee is caffeine. It is a stimulant that can help to improve alertness and concentration. Caffeine is also found in other plants, such as cocoa beans and kola nuts.

Nicotine is a stimulant that is found in tobacco. It is addictive and can cause a number of health problems, including cancer.

Chlorophyll is a green pigment that is found in plants. It is responsible for photosynthesis, the process by which plants convert sunlight into energy.

Aspirin is a pain reliever and fever reducer. It is not found in tea or coffee.