The presence of the enzyme is required in order for testosterone to be converted to this hormone is necessary for the differentiation of the select one: a. 5-alpha reductase; dihydrotestosterone; male external genitalia b. aromatase; testosterone; "gonadastat" along female lines c. 5-alpha reductase; estradiol; female internal genitalia d. hyaluronidase; dihydrotestosterone; female external genitalia e. hyaluronidase; estradiol; male external genitalia