The correct answer is: B. Compressive force.
Sewers are subjected to a lot of weight from the soil and other materials above them. This weight puts a compressive force on the sewer. The sewer must be strong enough to withstand this force without collapsing.
Tensile force is a force that pulls on an object. Bending force is a force that causes an object to bend. Shearing force is a force that causes two parts of an object to slide past each other.
Sewers are not typically subjected to tensile force, bending force, or shearing force. However, they may be subjected to these forces if they are not properly installed or if they are damaged.
It is important to design and install sewers so that they can withstand the compressive forces that they will be subjected to. This can be done by using strong materials and by making sure that the sewer is properly supported.