Lets explore the answer.
As we know the range of collision occurence is (0-pt) and of collision detection is (0-2*pt) where pt=propagation time.
Consider 4 stations:
A B C D
If collision occur between signals of A and D at position between C and D
then C will detect collision before 2*pt so it need to transmit some signal to all other stations that a collision had already occurred here you all please JAM your any more signal,don't transmit anything or it will also result in collision.
It keeps transmitting this Jamming signal till 2*pt till every channel get to know about collision and then after 2*pt they all go and implement Exponential back off algorithm..together