During an auscultatory blood pressure determination, the Korotkoff sounds that are listened for are produced because

B: Turbulent blood flow produces sound that is audible with a stethoscope. Auscultatory systolic BP measurement requires the artery to be squashed flat. At the point just before blood flow is stopped the blood squirts through the squashed artery in a turbulent fashion and this noisy squirting blood produces a sound audible with a stethoscope.