`A' a Hindu widow owned a house. On 28-4-63 she adopted `B' as her son and executed a deed of adoption. This document which is not registered also contains a covenant wherein she has stated that after this deed of adoption, her adopted son will be entitled to whole property and she will have no right to alienate any part of property. The widow (a) sold the house to C by registered sale deed. C filed a suit for possession against B on the basis of registered sale deed. B relied upon recital of adoption deed to plead that `A' had no right to sell the house. Decide.    (5 marks)