(7)Where—(a)any person buys or acquires any securities or unit within a period of three months prior to the record date;(b)such person sells or transfers—(i)such securities within a period of three months after such date; or(ii)such unit within a period of nine months after such date;(c)the dividend or income on such securities or unit received or receivable by such person is exempt,then, the loss, if any, arising to him on account of such purchase and sale of securities or unit, to the extent such loss does not exceed the amount of dividend or income received or receivable on such securities or unit, shall be ignored for the purposes of computing his income chargeable to tax.