Two discs are rotating about their axes, normal to the discs and passing through the centers of the discs. `Disc D_1` has 2 kg mass and 0.2m radius initial angular velocity of `50 rad s^-1`. Disc `D_2` has 4 kg mass, 0.1 m radius and initial angular velocity of `200 rad^s-1` The two discs are brought in Contact face to face, with their axes of rotation coincident The final angular velocity `(in rad s^-1)`of the system is

Options

A. 40
B. 60
C. 100
D. 120