Supplies manufactured in the United States shall be specified for all purchases and shall be purchased unless the City determines that:

(a) the supplies are not manufactured in the United States in reasonably available quantities;

(b) the price of the supplies manufactured in the United States exceeds by an unreasonable amount the price of available and comparable supplies manufactured elsewhere;

(c) the quality of the supplies manufactured in the United States is substantially less than the quality of comparably priced available supplies manufactured elsewhere; or

(d) the purchase of supplies manufactured in the United States is not in the public interest.