This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
A 14 year old boy present with headache fever and cough for 2 days. Sputum is scant and non purulent and gram stain reveals many white cells but no organisms. The treatment should be initiated with 
Select and explain. 
A. Cefazolin, B. Erythromycin, C. Amikacin, D. Trovafloxacin
B: Erythromycin
Answer: B: Erythromycin 
Explanation: Ref-KDT 6/e p729 Diagnosis is atypical pneumonia in the DOC is Erythromycin.