The correct answer is D. All the above.
Small sewers are cleaned by flushing. This is done by using a high-pressure hose to blast water into the sewer line. This can remove any debris or blockages that are causing the sewer to back up.
Medium sewers are cleaned by cane rodding. This is done by inserting a long, flexible rod into the sewer line. The rod is then used to break up any clogs or blockages.
Medium sewers may be cleaned by pills. These are small, round tablets that are inserted into the sewer line. The pills dissolve and release a chemical that helps to break down any clogs or blockages.
It is important to note that the method of cleaning a sewer will vary depending on the size of the sewer, the type of blockage, and the materials used to construct the sewer. It is always best to consult with a professional plumber to determine the best way to clean your sewer.