Aquifers are too high up in the mountains. The weight of the depot is too great over the aquifer. The fumes escaping from the fuel depot are explosive. If the fuel leaks, the water in the aquifer will become contaminated.
I gave my students this multiple choice question: Why is it not a safe practice to place a fuel depot over an aquifer?

Only one answer is correct among these 4 choices:
- Aquifers are too high up in the mountains.
- The weight of the depot is too great over the aquifer.
- The fumes escaping from the fuel depot are explosive.
- If the fuel leaks, the water in the aquifer will become contaminated.

Could you tell me which one is correct?

If the fuel leaks, the water in the aquifer will become contaminated.