(3)The provisions of sub-section (1) or sub-section (2) shall not apply if the owner, or the person who has had a beneficial interest in the securities, as the case may be, proves to the satisfaction of the Assessing Officer—(a)that there has been no avoidance of income-tax, or(b)that the avoidance of income-tax was exceptional and not systematic and that there was not in his case in any of the three preceding years any avoidance of income-tax by a transaction of the nature referred to in sub-section (1) or sub-section (2).
