Which artery carries deoxygenated blood instead of oxygenated blood?

The first heart sound occurs at:

The histology of the heart superficially shows the following structures, $EXCEPT$:

The human heart lies in the space present between the two lungs,which is called . . . . . . .

Starling's law is related to

$A$: Endocardium provides a smooth lining for the inside of the heart and covers the valves of the heart.
$R$: Endocardium is continuous with the endothelial lining of the large blood vessels associated with the heart and the rest of the cardiovascular system.