B is the survivor's special qualifying factor for the month, and C is the greater of zero and the amount determined by the formula (D x B) - 3/4 E where B is the survivor's special qualifying factor for the month, D is the pension equivalent in respect of the month, and E is the monthly income of the survivor in the current payment period rounded, where that income is not a multiple of four dollars, to the next lower multiple of four dollars; and ( c ) where the monthly income of the survivor in the current payment period is more than the product (i) obtained by multiplying four-thirds of the rounded pension equivalent in respect of the month by the survivor's special qualifying factor for the month, and (ii) rounded, where that product is not a multiple of four dollars, to the next higher multiple of four dollars, the amount determined by the formula (A x B) - C/2 where A is the supplement equivalent for the survivor in respect of the month, B is the survivor's special qualifying factor for the month, and C is the residual income of the survivor in respect of the month rounded, where that residual income is not a multiple of two dollars, to the next lower multiple of two dollars. Marginal note: Supplement equivalent for the survivor (4.1) The amount of the supplement equivalent for the survivor is ( a ) four hundred and fifty-four dollars and nine cents, for any