When Deficits in the Sense of Smell Have Been Studied,it

When deficits in the sense of smell have been studied,it has been found that smokers

A) are as likely as nonsmokers to have trouble detecting common odors.
B) who have smoked two packs a day for ten years must abstain from cigarettes for ten more years before the sense of smell returns to normal.
C) are twice as effective as nonsmokers at detecting danger by smelling a fire's smoke.
D) are likely to detect odors in the same manner as nonsmokers after quitting for one year.