In what order does blood flow through the heart starting from the superior and inferior vena cava?

The correct answer outlines the proper sequence of blood flow through the heart after it enters from the systemic circulation through the superior and inferior vena cava.

When deoxygenated blood returns to the heart, it enters the right atrium via the superior and inferior vena cava. After filling the right atrium, the blood then moves through the tricuspid valve and into the right ventricle. Following ventricular contraction, blood is ejected into the pulmonary artery, which carries it to the lungs for oxygenation. This sequence accurately represents the path of blood after it fills the right atrium.

Contextually, the other choices depict sequences that either skip crucial anatomical structures or incorrectly arrange the flow of blood. For instance, starting from the right ventricle and mentioning the aortic valve and aorta skips over several necessary steps, such as the blood first passing through the pulmonary valve and to the lungs. Additionally, the mention of the left atrium and mitral valve pertains to oxygenated blood returning from the lungs, but it does not relate to the initial question regarding the flow of blood starting from the superior and inferior vena cava. Therefore, option B correctly details the pathway of deoxygenated blood through vital chambers and valves in the heart.