Correct option is A
Systemic circulation begins in the left ventricle, where oxygenated blood is pumped into the aorta and distributed throughout the body. It ends in the right atrium after the deoxygenated blood returns via the vena cava. Pulmonary circulation starts in the right ventricle. Systemic circulation operates under higher pressure to deliver blood efficiently to all body tissues.
Explanation of options: (a) ✘ It starts in the right ventricle – Incorrect; that's where pulmonary circulation starts. (b) ✔ It is greater-pressure circulation – True; systemic circulation requires higher pressure for distant perfusion. (c) ✔ It ends in the right atrium – True; deoxygenated blood returns here before entering pulmonary circulation. (d) ✔ It starts in the left ventricle – True; oxygenated blood begins its systemic journey here.