A 9-year-old boy presents with fever, joint aches, and a rash for the past 2 days. His father is a physician

A 9-year-old boy presents with fever, joint aches, and a rash for the past 2 days. His father is a physician and started him on amoxicillin for a sore throat 8 days ago. A classmate was recently diagnosed with strep throat. One month ago he was successfully treated for acute otitis media with amoxicillin and has been well in the interim. On physical examination, he has posterior pharyngeal erythema without exudates and anterior and posterior cervical lymphadenopathy. There is periarticular swelling at the metacarpophalangeal joints, knees, wrists, and ankles, with dusky urticarial papules and plaques, prominent at the lateral aspect of the feet and hands, and at the junction of the sole and side of the foot. His current symptoms are most likely due to: A. Infectious mononucleosis B. Serum sickness-like reaction C. Penicillin allergy D. Rheumatic fever