A 45-year-old woman comes to the physician because of progressive facial swelling and pain during the past week. She has a 10-year history of poorly controlled type 1 diabetes mellitus. Physical examination shows ecchymoses over the left orbital and periorbital regions with proptosis. There is a necrotic lesion with a black eschar in the left naris. Findings on microscopic examination of material from the lesion include broad, irregularly shaped, nonseptate hyphae with branches at right angles. Which of the following is the most likely cause of the nasal lesion?
