Parents, friends, and relatives of children with asthma should try to stop smoking. Until they can successfully quit, they should smoke only outdoors, not in the home or in the family car. They should not allow others to smoke in the home, and should make sure the child's school is smoke-free. Which source would provide the MOST bias-free information about second hand smoke as a trigger of asthma? A) an advertisement by an air-purifying systems corporation B) an editorial by an asthma sufferer pushing for a ban on public smoking C) a pamphlet from a tobacco company about the dangers of secondhand smoke D) a brochure from the respiratory information council at Johns Hopkins University