A vertical conducting ring of radius R falls vertically with a speed V in a horizontal uniform magnetic field B which is
perpendicular to the plane of the ring 

When a conducting element travels perpendicular to a magnetic field, emf is induced in direction perpendicular to both velocity and field. Thus potential at D is greater than that at C and E, which are greater than that at A.
Hence, potential at D is higher than that at A.
Since, C and E are both along same line of velocity vector, there is no potential difference between them.