A 15-year-old girl presents to urgent care with a nonproductive cough and low-grade fever that developed insidiously over the previous week. Physical exam reveals diffuse rales on pulmonary auscultation, and chest X-ray shows diffuse non-focal infiltrates. Which of the following is the most accurate statement regarding this patient’s condition? Extrapulmonary manifestations may include hemolysis and CNS involvement Mycoplasma pneumoniae is the most common etiology in all age groups Penicillin is the most appropriate treatment The formation of cold agglutinins is a positive confirmatory test