Which of the following events could result in § 1250 depreciation recapture? a. Sale at a loss of a depreciable business building held more than one year. b. Sale at a gain of depreciable equipment held more than a year on which straight-line depreciation was taken. c. Sale at a loss of a depreciable business building held for nine months. d. Sale at a gain of qualified improvement property held more than a year on which bonus depreciation [§ 168(k)] was taken.