Step 1: Understanding the Concept:
The question asks for the properties that define clean, safe water (potable water).
Step 2: Detailed Explanation:
For water to be considered clean and safe for consumption, it must meet several criteria:
(A) Colourless: It should be clear and transparent, without any suspended particles or colour.
(B) Odourless: It should not have any smell, which could indicate the presence of chemicals or decaying organic matter.
(C) Germ free: It must be free from harmful microorganisms (pathogens) like bacteria and viruses that can cause diseases.
Since all three properties are essential characteristics of clean water, the correct answer is "All of these".
Step 3: Final Answer:
Clean water is colourless, odourless, and germ-free.