Which one of the following is a matching pair

Options

A. Lub - sharp closure of AV valves at the beginning of ventricular systole
B. Dub - sudden opening of semilunar valves at the beginning of ventricular diastole
C. Pulsation of the radial artery-valves in the blood vessels
D. Initiation of the heart beat Purkinje fibres

Answer

A

Explanation

Lub is the first(S1) sound of heart. it is caused by turbulence caused by closure of mitral and tricupside valve at the start of systole.