Answer: a. a reduced supply of usable water
Explanation:
I am unsure as to the text being referred to but this should be the correct answer.
The market allocates resources efficiently based on price. This means that it sets the price such that people who can afford the goods are able to buy them. This ensures that not everybody gets the good and the good can be sustainably used.
If the government imposes price controls on a good as they did here. The market would be unable to efficiently allocate the water so more people than before would be able to access it. This would lead to the supply being used up so there will be a reduced supply of the good which in this case is water.
