Answer:
Option-(A): To prevent leachate from seeping into groundwater.
Step-by-step explanation:
Sanitary landfill:
The system or the place where the waste materials are placed and stored in order to keeping the surrounding safe from its toxic effects. As these toxic waste products if reaches any healthy being or the places where the living beings are present( by means of households).
Purpose of the liner in a sanitary landfill:
The sanitary landfill structure consists of the liner in order to prevent any leachate from seeping into groundwater. As it will cause the disturbance inside the ecosystem and may cause many disorders or diseases inside the living beings.As the land fills are acting as the reservoir for storing the waste materials, while the liner acts as a layer or membrane which keeps the different levels of toxic materials away from reaching any groundwater or provide any damage to the healthy society.