In a reservoir the average volume of sediment deposition is 0.15 million cubic per year. If the dead storage and total capacity of the reservoir are 8 million cubic metres and 36 million cubic metres respectively,

• A. the reservoir will theoretically be silted in 240 years
• B. the reservoir will start reducing after 60 years
• C. both (a) and (b)
• D. neither (a) nor (b).