; or (II) another appropriate benchmark period, as determined by the Administration. (ii) Whether the amount charged by such person grossly exceeds the price at which the same or a similar housing unit was readily obtainable for rental or purchase in the same area from other sellers during the energy emergency period. (C) Mitigating factor The mitigating factor described in this subparagraph is whether the quantity of any housing dwelling units such person made available for rental or sale in an area covered by the proclamation during the 30-day period following the date on which the proclamation was issued increased over the quantity such person made available for rental or sale during the 30-day period before the date on which the proclamation was issued, taking into account any usual seasonal demand variation. (b) Affirmative defense It shall be an affirmative defense in any civil action or administrative action to enforce subsection (a), with respect to the renting out or sale of housing by a person, that the increase in the rental or sale price of such housing reasonably reflects additional costs that were paid, incurred, or reasonably anticipated by such person, or reasonably reflects additional risks taken by such person, to rent or sell such housing unit under the circumstances. (c) Rule of construction This section may not be construed to cover a transaction on a futures market. (d) Enforcement (1) HUD The Secretary of Housing and Urban Development shall enforce violations of subsection (a) of this section— (A) in the same manner, by the same means, and with the same jurisdiction, powers, and duties as the Federal Trade Commission has under the Federal Trade Commission Act ( 15 U.S.C. 41 et seq. ) with respect to violations of a rule defining an unfair or deceptive act or practice prescribed under section 18(a)(1)(B) of such Act ( 15 U.S.C. 57a(a)(1)(B) )