The regulations allow some employees-those with enclosed offices-but not others the opportunity to smoke at their desks. If it is assumed that the regulations should allow all employees equal opportunity to smoke, those who are currently denied this opportunity should be given it, and so secretaries who smoke should be offered enclosed offices. Therefore, choice D is the best answer. None of the other choices enables the conclusion to be properly drawn. Choice A tends to conflict with the conclusion, unless some enclosed offices are vacant. Choice B supports no conclusion about how secretaries should be treated, and choice C undermines the conclusion. Finally, nonsmokers already have equal protection from hazards, so choice E cannot be used to justify making any changes.