Extensive pit-dwellings have been identified at the two Neolithic sites of :

The Neolithic sites of Burzahom and Gufkral, located in the Kashmir Valley, are renowned for their characteristic pit-dwellings. These subterranean houses were circular or oval pits dug into the loessic soil, featuring plastered walls and post-holes for thatched roofs, likely designed to provide insulation against the harsh Himalayan winters.

• Burzahom: The first Neolithic site discovered in Kashmir, it shows evidence of unique burial practices and bone tools alongside pit-dwellings.
• Gufkral: Meaning "cave of the potter," this site also revealed extensive pit-dwellings and a transition from aceramic to ceramic Neolithic phases.

In contrast, sites like Piklihal, Maski, and Hallur (South India) are primarily associated with ash mounds and cattle herding, while Chirand (Bihar) is famous for its bone implements. Therefore, option D is the correct answer.