A motor cyclist is moving towards a stationary car which is emitting sound of 165 Hz. and a police car is chasing the motor cyclist blowing siren at frequency 176 Hz. If the speed of police car is 22 m s–1, then the speed of motor cyclist for which the motor cyclist hears no beats is
(a) zero
(b) 11 m s–1
(c) 22 m s–1
(d) 33 m s–1