The correct answer is: a) Prevent floodwaters from inundating areas.
Embankments are constructed along rivers to prevent floodwaters from inundating areas. They are usually made of earth or stone and are designed to withstand the force of flowing water. Embankments can be used to protect both urban and rural areas from flooding.
Option b) is incorrect because embankments are not used to provide irrigation. Irrigation is the process of watering crops, and it is usually done using canals, pipes, or sprinklers.
Option c) is incorrect because embankments are not used to generate hydropower. Hydropower is a form of energy that is generated by the flow of water. It is usually done using dams or turbines.
Option d) is incorrect because embankments are not used to facilitate navigation. Navigation is the process of moving ships and boats from one place to another. It is usually done using channels, buoys, or lighthouses.