The correct answer is D. All the above.
Sewer pipes are made of a variety of materials, including earthen ware, stone ware, and refractory clay. Each material has its own advantages and disadvantages, and the choice of material will depend on the specific application.
Earthen ware is a type of ceramic that is made from clay and fired at a low temperature. It is relatively inexpensive and easy to work with, but it is not as strong as other materials. Earthen ware sewer pipes are typically used for small-diameter pipes in residential applications.
Stone ware is a type of ceramic that is made from clay and fired at a higher temperature than earthen ware. It is stronger and more durable than earthen ware, but it is also more expensive. Stone ware sewer pipes are typically used for larger-diameter pipes in commercial and industrial applications.
Refractory clay is a type of clay that is resistant to high temperatures. It is used to make sewer pipes that will be exposed to high temperatures, such as those that are used in power plants and incinerators. Refractory clay sewer pipes are the most expensive type of sewer pipe, but they are also the most durable.
In addition to the material, the type of sewer pipe will also depend on the diameter of the pipe, the pressure rating of the pipe, and the type of joint used to connect the pipes.