In levelling between two points A and B on the opposite sides of a river, the level was first set up near A and the staff readings on A and B were 2.645 m and 2.30 m respectively. The level was then moved near B and set up; the respective staff readings then were 1.085 m and 1.665 m on A and B respectively. What is the true difference of level between A and B?

• A. A and B are at same level
• B. A is 0.5825 m below B
• C. A is 0.4625 m below B
• D. B is 0.5825 m below A