The correct answer is: B. Outfall sewer
An outfall sewer is a sewer that discharges sewage into a watercourse, such as a river or lake. It is the final part of the sewer system, and it is designed to transport sewage away from populated areas and into a safe location for treatment.
A main sewer is a large sewer that collects sewage from smaller sewers and carries it to an outfall sewer. A branch sewer is a smaller sewer that connects to a main sewer and carries sewage from a specific area. A house sewer is a sewer that connects to a branch sewer and carries sewage from a single house or building.
Outfall sewers are typically constructed of concrete or steel, and they are often lined with a material to prevent infiltration of groundwater. They are typically buried underground, and they may be equipped with valves to control the flow of sewage.
Outfall sewers are an important part of the sewer system, and they play a vital role in protecting public health and the environment.