157.5. Where a taxpayer disposes of an interest in a life insurance policy that is not an annuity contract, otherwise than as a consequence of a death, or of an interest in an annuity contract, other than a prescribed annuity contract, there may be deducted in computing his income for the taxation year in which the disposition occurs an amount equal to the lesser of(a) the aggregate of all amounts each of which is an amount that was included by virtue of sections 92.11 to 92.19 or paragraph c.1 of section 312 in respect of that interest in computing his income for the year or any preceding taxation year, and
(b) the amount by which the adjusted cost basis, within the meaning assigned by sections 976 to 977.1, to him of that interest immediately before the disposition exceeds the proceeds of the disposition, within the meaning assigned by paragraph b.4 of section 966, of the interest that the policyholder, a beneficiary or an assignee became entitled to receive.