The correct options are
A Earthquakes
C Landslides
D Floods
The floodgates of the dams are usually opened to pass the excess water. However, if this is not done in a controlled manner, the downside river may start overflowing and cause floods in the nearby areas. Floods of Gujarat and Maharashtra in 2006 were aggravated when water was released from dams after heavy rainfall. Dams sometimes can also cause earthquakes.
Additionally, multi-purpose dams also cause soil erosion and water-borne diseases and pollution.