Answer:
B) Regurgitation
Step-by-step explanation:
Regurgitation refers to the backward flow of blood due to any reasons. Presence of atrioventricular valves between atrium and ventricle prevents the regurgitation, that is backward flow of blood. Structural or functional damage of any atrioventricular valves does not allow them to prevent the regurgitation.
Example: Valvular insufficiency is the condition wherein the cusps of the valves (mostly the mitral valve) become stiff and leads to backward flow of blood.