Here's a problem to solve: Which environmental risk is not associated with the disposal of used motor oil from cars?

Among the 4 following options, which is the correct answer?

- A: It is insoluble and difficult to clean up.
 
- B: It dissolves in water and causes acid rain.
 
- C: It enter storm drains and contaminates surface water.
 
- D: It leaks onto the ground and contaminates soil and ground water.
 