Correct Option: D  [ Forests ]
Remark:
Silviculture is the branch of forestry concerned with the management, cultivation, and care of forests. It involves the practice of controlling the establishment, growth, composition, and quality of forest stands to meet diverse needs such as timber production, wildlife habitat, and environmental conservation. The term comes from Latin — silva meaning forest, and cultura meaning cultivation.
Other options (for context)
- Rivers: Managed under hydrology or water resource management, not silviculture.
- Lakes: Managed under limnology or aquatic resource management.
- Hills: May be part of forest areas, but silviculture specifically refers to forest management.