The ring R in the arrangement shown can slide along a smooth, fixed, horizontal rod XY. It is attached to the block B by a light string. The block is released from rest, with the string horizontal.
(A) One point in the string will have only vertical motion
(B) R and B will always have momenta of the same magnitude.
(C) When the string becomes vertical, the speed of R and B will be directly proportionaly to their masses
(D) R will lose contact with the rod at some point