Answer:
The correct answer will be option-A.
Explanation:
The cardiac cycle of the heart is divided into two phases: contraction (systole) and relaxation (diastole).
The atria and ventricles of the heart contract simultaneously in response to the impulse generated in the SA node. The contraction of the atria and ventricles push the blood or pumps the blood.
The atrial systole pumps blood to ventricles whereas the ventricular systole pumps blood to the body parts.
Thus, option-A is the correct answer.
