668. For the purposes of sections 28 and 727 to 737, except as they apply to Title VI.5 of Book IV, an amount of a trust’s net taxable capital gains for a particular taxation year of the trust is deemed to be a taxable capital gain, for the taxation year of a taxpayer in which the particular year ends, from the disposition by the taxpayer of capital property if(a) the amount is designated by the trust, in respect of the taxpayer, in the trust’s fiscal return filed under this Part for the particular year and may reasonably be considered, having regard to all the circumstances including the terms and conditions of the trust arrangement, to be part of the amount that, because of any of sections 659, 661 and 662 or paragraph a of section 663, was included in computing the income for that taxation year of the taxpayer;
(b) the taxpayer isi. in the particular year, a beneficiary under the trust, and
ii. resident in Canada, unless the trust is, throughout the particular year, a mutual fund trust;
(c) the trust is, throughout the particular year, resident in Canada; and
(d) the aggregate of all amounts each of which is an amount designated, under this section, by the trust in respect of a beneficiary under the trust in the trust’s fiscal return filed under this Part for the particular year is not greater than the trust’s net taxable capital gains for the particular year.