Select from the following. (A). evaporation (B). vaporization (C). Dipping a magnet into it (D). hydration (E). Mixing in heavy metals (F). Cooking (G). Boiling it (H). Adding purified water to it

Fact 1: Treating water is used to remove harmful substances before drinking. Fact 2: Boiling is the safest method of treating water. Given the two facts above, what can be done to water to remove harmful substances before drinking?
Answer:
(G).