Cash credits.

 ¹³68.  ¹⁴Where any sum is found credited in the books ¹⁵ of an assessee maintained for any previous year, and the assessee offers no explanation about the nature and source thereof or the explanation offered by him is not, in the opinion of the ¹⁶[Assessing] Officer, satisfactory, the sum so credited may be charged to income-tax as the income of the assessee of that previous year.