In mid-december, a woman with insulin-dependent diabetes who had been on prednisone fell and received an abrasion on the dorsal side of her right hand. she was placed on penicillin. by the end of january, the ulcer had not healed, and she was referred to a plastic surgeon. on january 30, a swab of the wound was cultured at 35°c on blood agar. on the same day, a smear was made for gram staining. the gram stain showed large (10 µm) cells. brownish creamy colonies grew on the blood agar at 35°c. cultures set up on february 1 and incubated at 25°c showed filamentous growth with septate hyphae. the most likely cause of the infection is aa) gram-negative bacterium. b) dimorphic fungus. c) parasitic alga. d) yeast. e) pleomorphic protozoan.