Systemic circulation in the cardiac system refers to

The correct option is "carry blood to the right side of the heart".

To understand why this option is correct, let us break down the double circulatory system of the human body, which consists of pulmonary circulation and systemic circulation.
In the cardiovascular system, blood flows in a continuous loop through two main circuits:

1. Pulmonary Circulation: Deoxygenated blood is pumped from the right side of the heart (right ventricle) to the lungs, where it picks up oxygen and releases carbon dioxide. The oxygenated blood then returns to the left side of the heart (left atrium).
2. Systemic Circulation: Oxygenated blood is pumped from the left side of the heart (left ventricle) to all the organs, tissues, and cells of the body to deliver oxygen and nutrients. As the body uses the oxygen, the blood becomes deoxygenated and is eventually collected and returned back to the right side of the heart (specifically, the right atrium via the vena cava) to complete the circuit.

Consequently, the final destination and endpoint of the systemic circulation loop is to return and carry this deoxygenated blood back to the right side of the heart, where it can then enter pulmonary circulation to be re-oxygenated.