Read the following statements and find out the correct statement.                       

a) Heart is situated in the thoracic cavity, is between the two lungs, slightly tilted to the right.

b) Heart has the size of a clinched fist.

 c) Heart is protected by double walled membranous bag, pericardium, consist the pericardial

 fluid.

 d) Human heart has four chambers, two relatively larger upper chambers called atria and two smaller lower chambers called ventricles.

e) A thick muscular wall called the inter - atrial septum separates the right and the left atria whereas a thin-walled, the inter-ventricular septum, separates the left and right ventricles.