The patient is exhibiting signs of group A streptococcal pharyngitis, which is treated with penicillin. The emancipated minor who is 15 years old may have difficulty obtaining the 10-day oral prescription; he or she may also be at risk for treatment failure for the 10-day course, which can lead to reinfection and other serious consequences. Therefore, a single IM dose of penicillin G benzathine is the best option. Because of the weight greater than 27 kg, the 1.2M unit dose is the most appropriate prescription for the patient. If the patient weighed less than 27 kg, then the 600,000 unit dose IM would be appropriate. The oral doses are both appropriate for the patient’s weight and age, but the 10-day oral dosing is not the best option for this patient.