The correct option is A Submerge
In recent years, multi-purpose projects and
large dams have come under great scrutiny
and opposition for a variety of reasons.
Regulating and damming of rivers affect their
natural flow causing poor sediment flow and
excessive sedimentation at the bottom of the
reservoir, resulting in rockier stream beds and
poorer habitats for the rivers’ aquatic life. Dams
also fragment rivers making it difficult for
aquatic fauna to migrate, especially for
spawning. The reservoirs that are created on
the floodplains also submerge the existing
vegetation and soil leading to its decomposition
over a period of time.