Figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its function/s,

A

D-Dorsal aorta -takes blood from heart to body parts ,$$PO_{2}$$=95 mm Hg

B

A-Pulmonary vein -takes impure blood from body parts , $$PO_{2}$$=60 mm Hg

C

B-Pulmonary vein -takes impure blood from heart to lungs , $$PO_{2}$$=90 mm Hg

D

C-Venacava-takes blood from body parts to right auricle , $$PCO_{2}$$=45 mm Hg