The system of a network of pipes used for taking away wastewater is called (b) sewerage.
Explanation:
Sewerage: refers to the overall system of pipes, pumps, and related infrastructure that transports wastewater from its source to a treatment facility.
Sewers: are the individual pipes that make up the sewerage system.
Transport system: is a general term and doesn’t specifically refer to wastewater conveyance.
Treatment plant: is the facility where wastewater is processed, not the system that conveys it there.