If a Physician Hears Abnormal Heart Sounds While Examining a Patient

If a physician hears abnormal heart sounds while examining a patient with a stethoscope, this would most likely indicate a problem with

A) the firing of the sinoatrial node.
B) the contraction of the heart muscle.
C) the function of the heart valves.
D) the electrical signal from the muscles of the ventricles.
E) the flow of blood into the atria.