A 25-year-old woman sees her physician because of hirsutism (inappropriate hair growth)and excessive acne.During examination,her blood pressure is 150/90 mm Hg (elevated).Blood work reveals normal Na⁺ levels but low/normal K⁺ levels.Testosterone and dihydrotestosterone (DHT)levels are in the high end of the normal range,and the levels of dehydroepiandrosterone sulfate (DHEAS)and adrenocorticotropic hormone (ACTH)are moderately elevated.Her physician suspects late-onset congenital adrenal hyperplasia resulting from subnormal activity of an adrenal enzyme.The subnormal activity of which enzyme explains both the elevated adrenal androgens (e.g.,DHEAS)and hypertension (elevated blood pressure)?