A toy with reciprocating movement is shown. As the wheels of the toy rotate, the head is required to reciprocate. If given options are indicative of conversion of rotary to linear motion using a disc located at the centre of the wheel shaft, which option will result in the required movement when the toy is pushed forward? Assume a working spring loaded cam mechanism in the relevant option/s. [This question contains an animated GIF image.] (In the exam this image was animated. Only a still frame is available here.)