Which of the following factors governs the design period of water supply structures?
1. Useful life of component structures.
2. Amount and availability of additional investment.
3. Rate of population growth.
4. Rate of intrest on the borrowings.
1
1, 2 and 3
2
1, 3 and 4
3
2, 3 and 4
4
1, 2, 3 and 4