Since this is an isobaric chart, all four points have the same pressure, 500 mb.  The numbers on the contour lines are altitudes in meters.  The 500 mb pressure level is found at higher altitude than the 850 mb level used in the previous examples.

At 5400 m, Point A is found at lowest altitude.  The coldest air in the picture is between the ground and Point A.  That is why Point A is closest to the ground.

The warmest air is found between the ground and Point D.  Point D is found at highest altitude, 5640 meters.

The winds (yellow arrows) on upper level charts blow parallel to the height contours.  This winds are blowing straight from west to east at Point C.