You are presented with the quiz "Carpooling does what to the amount of cars and traffic congestion?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "carpooling decreases the amount of cars used to travel to a place" and "car crashes also create traffic congestion and greatly disrupt travel for commuters". 

So, what's the best answer to the question?


 

        decreases   