The line of collimation method of reduction of levels, does not provide a check on A. Intermediate sights B. Fore sights C. Back sights D. Reduced levels

The correct answer is: C. Back sights

The line of collimation method of reduction of levels is a method of reducing the level of a point by taking two sights, one to the point and one to a benchmark. The difference in the two readings is the reduced level of the point.

The line of collimation method does not provide a check on the back sights because the back sight is not used to calculate the reduced level of the point. The back sight is only used to set the instrument and to check the horizontality of the line of sight.

The other options are incorrect because they are all used to calculate the reduced level of the point.

• Intermediate sights are the sights taken between the back sight and the fore sight.
• Fore sights are the sights taken to the point being leveled.
• Reduced levels are the elevations of points above or below a datum plane.