You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Predisposing factors for skin cancer are-a)  Smokingb)  U-V-light c)  Chronic ulcerd)  Infrared light and explain in detail?
Exposure to Sun (UV rays) Major predisposing factors.                    o Old burn scars
Industrial carcinogens (Tars and oils)                                                    o Ingestion of arsenicals
Chronic ulcers and draining osteomyelitis.                                           o Ionizing radiation

Note : Cigarette smoking and tobacco & betel nut chewing are predisposing factors for squamous cell carcinoma of lips and oral cavity.