The figure shows blood circulation in humans with labels A to D. Select the option which gives correct identification of label and functions of the part.
D - Pulmonary Vein-Takes oxygenated blood to heart, PO2 = 95 mmHg
C - Vein-Thin walled and blood flows evenly.
B - Capillary-Thin without muscle layer and wall one cell layer thick (squamous epithelium).
A - Artery-Thick walled and blood flows in jerks.