Well, since C is the only example where a positive thing happens, then it is certainly not a potential problem, so 'they can provide a lot of energy for people to use' is the correct answer. The other examples are problematic.
Answer:
1) Which areas of the state seem to be affected?
- In order to find out the location of what's going wrong to examine it further.
2) What experts have been consulted on the water quality issue in the state?
- To make sure the water is okay to drink.
3) What water testing has been done to determine if there are water quality issues?
- To have a certain evaluation of the water and its conditions.
