Which of the Following Correctly Describes How Bottled Water and Public

Which of the following correctly describes how bottled water and public water supplies are purified?

A) Both are usually purified using X-rays.
B) Both are usually purified using ozone.
C) Bottled water is usually purified using chlorine, but public water supplies are usually purified using X-rays.
D) Bottled water is usually purified using ozone, but public water supplies are usually purified using chlorine.