A 65-year-old male presents to an emergency room in the US. He complains of a 6-month history of night sweats, fever, and cough with the production of sputum. He also states that he has lost 30 pounds in the last year. He denies illegal drug use, but admits to having sex with men. He demonstrated positive immunodeficiency virus serology and a low CD4^+ lymphocyte count. Gram stain of his sputum demonstrated thin rods that did not stain. When these organisms were stained with the Acid-Fast stain, they took up the stain. He is most likely to be infected with which of the following Mycobacterium? A. avium-complex B. scrofulaceum C. tuberculosis D. hominis E. pneumoniae