Two horizontal circular discs of different radii are free to rotate about their central axes. One disc is given some angular velocity and the other is stationary. Their rims are now brought in contact. Their is friction between the rims. Correct statement from the following is

Question

(A) Force of friction between the rims will disappear when the disc rotate with same angular speeds. (B) Force of friction between the rims will disappear when they have equal linear velocities. (C) Angular Momentum of the system is conserved (D) Rotational Kinetic Energy of the system is conserved.

$\begin {array} {1 1} (1)\;(D) & \quad (2)\;(C) \\ (3)\;(B) & \quad (4)\;(A) \end {array}$