In the formula in subparagraph a of the first paragraph,(a) A is the amount of principal owed by the corporation under the foreign currency debt at the measurement time, calculated using the exchange rate applicable at that time;
(b) B is the portion of any gain, previously recognized in respect of the foreign currency debt because of this Title, that is reasonably attributable to the amount determined under subparagraph a; and
(c) C is the portion of any capital loss, previously recognized in respect of the foreign currency debt because of this Title, that is reasonably attributable to the amount determined under subparagraph a.