Answer the following question given this paragraph: 

The water Americans get from their faucets is safe. This water has been treated and purified. At least 20% of the world’s people do not have clean drinking water always available. That's more than 1 billion people. They must drink water from where they can get it. Maybe straight from a river or pond ( Figure below ). Human wastes may be in the water. If that's the case, the water will probably contain pathogens. Pathogens are organisms that cause diseases.


Q: At least 20 percent of the world’s people do not have a ready supply of what?

 Choices:

- clothing

- food

- oil

- clean drinking water

A:
clean drinking water
