The correct option is D William Harvey
English physician William Harvey is one of the most important cardiovascular investigators of all times. Until Harvey's discovery, doctors had relied on the 1300-years old teachings of a Greek physician named Galen, whose concept was that blood was created by the liver and then consumed by the living tissues. Later Harvey argued that the amount of blood in the living body is fixed and constantly circulates inside the body, being refreshed by passing through lungs and other organs; this led to the discovery of circulation of blood.