Two identical thin rings each of radius R are coaxially placed at a distance R. If the rings have a uniform mass distribution and has mass m1 and m2 respectively, then the work done in moving a mass m from centre of first ring to that of the other is:
(A) zero
(B) 2RGm(m1−m2)(2−1)
(C) RGm2(m1+m2)
(D) m2RGmm1(2+1)