Answer:
OptionA, re heard as a high pitched click when the valve should be—but is not—wide open during systole.
Step-by-step explanation:
Heart murmurs are sound that are heard when the blood flow into the left ventricle but the flow get reduced as compared to the normal flow. The flow reduction happens because of the stenotic valve which has a narrow opening as compared to the opening in valves of a normal heart. Due to reduced valve size, the blood flow becomes fast and turbulent thereby producing murmur sound.
Hence, option A is correct