The patient with Marfan syndrome is at risk for mitral valve prolapse, which presents with fatigue, orthopnea, and a holosystolic murmur with heave that is denoted in the phonocardiogram option C. Option A is a normal phonocardiogram; the patient has symptoms of a heart lesion, so this is unlikely. Option B indicates the crescendo/decrescendo murmur that extends through diastole and systole associated with patent ductus arteriosus, a common heart lesion associated with prematurity. Aortic stenosis is represented in option D with the crescendo/decrescendo murmur during systole only.