Laying of sewers is usually done with the help of A. A Theodolite B. A compass C. Sight rails and boning rods D. A plane table

The correct answer is: C. Sight rails and boning rods.

Sight rails and boning rods are used to lay sewers because they are a simple and accurate way to ensure that the sewer is laid in a straight line. The sight rails are placed on either side of the trench, and the boning rods are used to sight along the rails to make sure that the sewer is in line.

A theodolite is a surveying instrument that is used to measure angles. It is not typically used for laying sewers, as it is not as accurate as sight rails and boning rods.

A compass is a device that is used to determine direction. It is not typically used for laying sewers, as it is not as accurate as sight rails and boning rods.

A plane table is a surveying instrument that is used to make maps. It is not typically used for laying sewers, as it is not as accurate as sight rails and boning rods.