Unexplained expenditure, etc.
69C. Where in any financial year an assessee has incurred any expenditure and he offers no explanation about the source of such expenditure or part thereof, or the explanation, if any, offered by him is not, in the opinion of the 76[Assessing] Officer, satisfactory, the amount covered by such expenditure or part thereof, as the case may be, may be deemed to be the income of the assessee for such financial year.]