Conclusion: water rationing will not be necessary this summer.
Why? Heavy rainfalls in the metropolitan area have filled the reservoirs and streams.
We are looking for the answer choice that weakens the argument.
If anything, answer choice (A) strengthens the argument that water rationing will not be necessary this summer since answer choice (A) states that water rationing was imposed in the city in three of the last five years and we recently got unexpectedly heavy rainfalls in the metropolitan area this year that have filled the reservoirs and streams.
Answer choice (B) does nothing to the argument since our reasoning that we will not need to ration water this summer is due to the recent unexpectedly heavy rainfall, which filled the reservoirs and streams. Whether or not a small part of the city's water supply is obtained from deep underground water systems that are not reached by rainwater has no effect on the argument. We simply do not have enough information. It could be that such a small amount of the city's water supply is obtained from the underground water systems that the heavy rainfall has completely annulled the underground water systems contribution.
Again, if anything, answer choice (D) strengthens the conclusion that water rationing will not be necessary this summer. If there are lower-than-average temperatures this summer, then less water will evaporate. So, we will have even more water than expected.
Answer choice (E), if anything, could also strengthen the argument. If, for most years in the city, the summer has less total precipitation than any other season, then this low amount of precipitation is considered standard, i.e. less precipitation is expected. So, since we recently had UNexpectedly HEAVY rainfalls, i.e. water levels could have exceeded expectations, we have more evidence for the water rationing not being necessary.
Answer choice (C) is the only answer choice that weakens the argument. Regardless of the evidence that we had unexpectedly heavy rainfall, the fact that the water company's capacity to pump water to customers has not been able to keep up with the increased demand created by population growth could show that there still is a need for water rationing. Population growth is an added factor that helps us nullify or weaken the premise of extra water from rainfall.
Thus, answer choice (C) is the correct answer.
Hope that clears things up! Please let us know if you have any other questions.
