A 22-year-old college student presents with 2 weeks of low grade fevers, dry cough, malaise, myalgias, headache, and decreased appetite. A chest x-ray shows diffuse, interstitial, patchy infiltrates....

A 22-year-old college student presents with 2 weeks of low grade fevers, dry cough, malaise, myalgias, headache, and decreased appetite. A chest x-ray shows diffuse, interstitial, patchy infiltrates. What is the first-line antibiotic for this illness?

A. Azithromycin

B. Doxycycline