Which Cardiac Chambers Have the Thinnest Wall and Why

Which cardiac chambers have the thinnest wall and why?

A) The right and left atria; they are low-pressure chambers that serve as storage units and conduits for blood.
B) The right and left atria; they are not directly involved in the preload, contractility, or afterload of the heart.
C) The left ventricle; the mean pressure of blood coming into this ventricle is from the lung, which has a low pressure.
D) The right ventricle; it pumps blood into the pulmonary capillaries, which have a lower pressure compared with the systemic circulation.