As per my knowledge, DC - District Commisioner, is responsible for converting revenue land to residential. The land is eligible for residential use only if it is DC converted. If you are planning to build a house with B khata (form B register), it is better to go for DC converted sites otherwise BBMP will not sanction the building plan. Else you have to go for original khata (also called A khata) sites. I feel it is better to go for a DC converted land.