The given figure shows schematic plan of blood circulation in humans with labels A to D. Identify the label and give its functions?

 

• A

   C - Vena Cava - takes blood from body parts to right auricle, Pco2 = 45 mm Hg

• B

   D - Dorsal aorta - takes blood from heart to body parts,Po2 = 95 mm Hg
   

• C

   A - Pulmonary vein - takes impure blood from body parts, Po2 = 60 mm Hg

• D

  B - Pulmonary artery - takes blood from heart to lungs, Po2 = 90 mm H g.