Which of the Following May Explain Why Smokers Obtain More

Which of the following may explain why smokers obtain more pleasure from smoking in the morning than late in the afternoon?

A) Nicotine receptors are in the open state in the morning.
B) Nicotine receptors are in the closed state in the evening.
C) Abstinence from nicotine has reset their nicotine receptors to the closed state.
D) Smoking decreases the number of nicotine receptors in the brain.
E) Smoking decreases the number of nicotine receptors outside the brain.