In the third match of a volleyball tournament, a 15-year-old girl jumps up for a block and collapses. Despite cardiopulmonary res us citation, she cannot be revived. She had been healthy all her life and complained only of limited episodes of chest pain in games during the current school year. Which of the following pathologic findings of the heart is the medical examiner most likely to find? (A) Haphazardly arranged hypertrophied septal myocytes (B) Extensive myocardial hemos iderin deposition (C) Tachyzoites within foci of myocardial necrosis and inflammation (D) Mitral valvular stenosis with left atrial enlargement (E) Large, friable vegetations with destruction of aortic valve cusps