What is the role of ultraviolet (ultra-violet, UV) radiation in water purification systems? 1. It inactivates / destroys harmful microorganisms present in water. 2. It removes all the undesirable odors present in the water. 3. It accelerates the sedimentation of solid particles present in water, removes turbidity and improves the purity of water.

• A. only 1
• B. 2 and 3
• C. 1 and 3
• D. all these