68. Cash credits.

Where any sum is found credited in the books of an assessee maintained for any previous year, and assessee offers no explanation about the nature and source thereof or the explanation offered by him is not, in the opinion of the [1][Assessing] Officer, satisfactory, the sum so credited may be charged to income-tax as the income of the assessee of that previous year.

[2][[3][Provided that where the sum so credited consists of loan or borrowing or any such amount, by whatever name called, any explanation offered by such assessee shall be deemed to be not satisfactory, unless