Prolonged exposure to nonionizing radiation -- electromagnetic radiation at or below the frequency of visible light -- increases a person' s chances of developing soft-tissue cancer. Electric power lines as well as such electrical appliances as electric blankets and video-display terminals are sources of nonionizing radiation. Which one of the following conclusions is best supported by the statements above? ["Soft-tissue cancers are frequently cured spontaneously when sources of nonionizing radiation are removed from the patient's home.", 'People will short-term exposure to nonionizing radiation are not at risk of developing soft-tissue cancers.', 'Soft-tissue cancers are more common than other cancers.', 'Certain electrical devices can pose health risks for their users.']