Legal heir nominee complicated

Hi, BACKGROUND  If a person 'A' dies and leave behind two legal heirs 'B' & 'C'. 'A' nominates 'B' as his nominee on his bank account. 'C'  tells 'B'  that  he does not wish to take any inheritance and 'B' can keep all the money. 'B' receives the money from the BANK as the nominee and transfers it to his personal bank account. Question Does 'C' now need to make a Gift Deed in favour of 'B' ? If yes does the gift deed needs to be registered or simply signed on Stamp paper and notarized? Who is liable to tax on the interest generated in B's bank account after the transfer from deceased's account ? Thanks Shanti