Explanation:

Only statements 1&2 are correct.

• The Standing Committee of the National Board for Wildlife (NBWL), chaired by Union Environment Minister has approved a proposal to carry out oil and gas exploration in the eco-sensitive zone of the Hollongapar Gibbon Wildlife Sanctuary in Assam's Jorhat district.

• Location: It is located in the Jorhat district of Assam, India.

• It is the only sanctuary in India named after a gibbon due to its distinction for containing the densest gibbon populations in Assam.

• It is situated at an altitude between 100 and 120 m (330 and 390 ft), the topography gently slopes downward from southeast to northwest.

• River: The Bhogdoi River creates a waterlogged region dominated by semi-hydrophytic plants along the border of the sanctuary. It is not drained by the River Brahmaputra.

• It contains India’s only gibbons–the hoolock gibbons, and Northeastern India’s only nocturnal primate–the Bengal slow loris. 

Hence option 2nd is correct.