A point object O is placed at a distance of 20 cm from a convex lens of focal length 10 cm as shown in figure. At what distance x from the lens should a concave mirror of focal length 60 cm, placed so that final image coincides with the object ?
A. 10 cm
B. 40 cm
C. 20 cm
D. final image can never coincide with the object in the given conditions