epicylic gear train

Question

1. The arm OA of an epicylic gear train shown in Fig. revolves counter clockwise about O with an angular velocity of 4 rad/s. Both gears are of same size. The angular velocity of gear C, if the sun gear B is fixed, is                                                                                                                                                                       

 

      (a) 4 rad/s                                                           (b) 8 rad/s

      (c) 10 rad/s                                                         (d) 12 rad/s