The right option is; c. can be used and consumed without risk
The defining characteristic of potable water is that it can be used and consumed without risk.
Potable water is the water that is considered safe for human consumption without risk of health problems. Potable water meets drinking water quality standards in terms of physical, chemical and microbiological parameters. Potable water has been treated and it is assumed to be considerately free of harmful pathogens such as bacteria and contaminants.
I attached a PDF document, just take a part of it that seems to work the best, and put it through a paraphrasing tool so it doesn't get flagged for plagiarism
