Which of the following are the principal factors influencing the choice of a particular method of lining?1. Availability and cost of the material at the site or within easy reach2. Velocity of flow in the channel3. Cost of maintenance

• A. 1 and 2 only
• B. 1 and 3 only
• C. 1, 2 and 3
• D. 2 and 3 only