In which case oral evidence cannot be given?

A' hired lodgings of 'B' and gives to 'B' a card on which he wrote "Rooms, Rs. 2000/- a month". 'A' in a suit wants to prove verbal agreement that the terms included partial board

A' hired lodgings of 'B' for a year. A regularly stamped agreement was drawn up by an attorney and signed by both of them. The document is silent on the subject of board. 'A' in a suit wants to prove verbal agreement that the terms included partial board.

Both in A and in B