you can't really specify which is the best hospital for DNB ctvs because at your rank you will be getting DNB ctvs and only a few colleges and not the top once all do you have good chances of making it through as of West Bengal I can tell you Rabindranath Tagore institute of cardiovascular sciences is the most reputable 1 and you could fly over there for further information on this you could also check out the previous years DNB seat allotment portals and check out if there is any other college which would be more convenient to us par residency or matters of fulfilling the standards of education you are aiming at although it is always account statement made that DNB is easier to crack and difficult to pass so the level of difficulty will be almost the same because your examination centre will be an external centre and in the sixth year course you also don't have the option of changing your superspeciality if you think it is not according to your aptitude later on