A 4-year-old girl is brought to the emergency department after a syncopal episode during soccer practice. Her mother reports a 6-month history of exercise-induced dyspnea and chest pain with activity. She denies recent illness, fever, or orthopnea. Vital signs: BP 115/70 mmHg, HR 108/min, RR 24/min, SpO2 98% on room air. Physical examination reveals a prominent apical impulse, a harsh systolic ejection murmur best heard at the left lower sternal border that increases with standing and decreases with squatting, and a normal S2 with no diastolic murmur. Echocardiography shows asymmetric septal hypertrophy with systolic anterior motion of the mitral valve and left ventricular outflow tract obstruction with a peak gradient of 68 mmHg. Which of the following is the most likely diagnosis?

1. A)Aortic stenosis
2. B)Dilated cardiomyopathy
3. C)Hypertrophic cardiomyopathyGABARITO
4. D)Restrictive cardiomyopathy
5. E)Ventricular septal defect with aortic regurgitation