Final answer:
Option (B), William Harvey was the scientist who first described the heart's function as a pump for the circulatory system.
Step-by-step explanation:
The scientist who first described the manner in which the heart functions as a pump that continually circulates the blood was William Harvey. Harvey detailed the systemic circulation and properties of blood being pumped to the brain and body by the heart in his work Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus. His descriptions laid the foundation for modern understanding of circulatory system and heart function.
The heart acts as a muscular pump that moves blood into major vessels such as the aorta and pulmonary trunk, enabling the distribution of blood to the entire body. In essence, the heart plays a critical role in maintaining the movement of blood through two circulatory routes: the pulmonary and systemic circuits.