<prompt> Predisposing factors for skin cancer are-a Smokingb U-V-light c Chronic ulcerd Infrared lightbccacad  <response>: Exposure to Sun UV rays Major predisposing factors. o Old burn scarsIndustrial carcinogens Tars and oils o Ingestion of arsenicalsChronic ulcers and draining osteomyelitis. o Ionizing radiationNote : Cigarette smoking and tobacco betel nut chewing are predisposing factors for squamous cell carcinoma of lips and oral cavity. 