Smoking cigarettes causes lung cancer because A. nicotine destroys the membranes of alveoli, the microscopic air sacs. The alveoli expand, and the person cannot completely exhale. B. nicotine is deposited as black, sticky tar in respiratory passages. C. nicotinic receptors in the lungs bind carcinogens in cigarette smoke. D. nicotine binds the A1 allele of the dopamine D(2) receptor. E. nicotine accelerates the cell cycle of lung cells.