Teenager presents with fever, exudative pharyngitis, splenomegaly & posterior lymphadenopathy. CBC shows atypical lymphocytosis. What is the diagnosis and treatment?

a) Infectious mononucleosis (EBV); Supportive care
b) Streptococcal pharyngitis; Penicillin or amoxicillin
c) Kawasaki disease; High-dose aspirin and IV immunoglobulin
d) Acute retroviral syndrome (HIV); Antiretroviral therapy