A 32-year-old woman has had a chronic cough with fever for the past month. On physical examination, her temperature is 37.5deg C. A chest radiograph shows many small, ill-defined nodular opacities in all lung fields. A transbronchial biopsy specimen shows interstitial infiltrates with lymphocytes, plasma cells, and epithelioid macrophages. Which of the following infectious agents is the most likely cause of this appearance?
Candida albicans Cytomegalovirus Enterobacter aerogenes Mycobacterium tuberculosis