Please answer the following question: Fact 1: Lung cancer is most often caused by exposure to tobacco smoke. Fact 2: Secondhand smoke is also known as Environmental Tobacco Smoke. Given the two facts above, answer the question "What can be caused by secondhand smoke?" with the following options: - clean air - fresh scent - Toxicity - Pollution - negative - lung cancer - healthy lungs - Dehydration
A:
lung cancer