; and (ii) includes a biological product (as defined in section 351 of the Public Health Service Act). (3) Certain health plan expenses treated as wages (A) In general For purposes of paragraph (1), the term wages shall include so much of the eligible employer’s qualified health plan expenses as are properly allocable to such wages. (B) Qualified health plan expenses For purposes of this paragraph, the term qualified health plan expenses means amounts paid or incurred by the eligible employer to provide and maintain a group health plan (as defined in section 5000(b)(1)), but only to the extent that such amounts are excluded from the gross income of employees by reason of section 106(a) of such Code. (C) Allocation rules For purposes of this paragraph, qualified health plan expenses shall be allocated to qualified wages in such manner as the Secretary may prescribe. Except as otherwise provided by the Secretary, such allocation shall be treated as properly made if made on the basis of being pro rata among employees and pro rata on the basis of periods of coverage (relative to the periods to which such wages relate). (4) Distressed zone The term distressed zone means a population census tract— (A) which has been designated as a qualified opportunity zone under section 1400Z–1, and (B) which has a poverty rate in excess of 30 percent for the calendar year prior to the calendar year that includes the date of enactment of this section. (c) Special rules (1) Reduction in basis If a credit is determined under this section with respect to any property by reason of any qualified production activity expenditures described in subsection (b)(1)(B), the basis of such property shall be reduced by the amount of the credit so determined. (2) Coordination with other credits Any qualified production activity expenditures taken into account in determining the amount of the credit under subsection (a) shall not be taken into account in determining a credit under any other provision of this chapter. (3) Limitation on wages taken into