The bonds of the authority must be authorized by a resolution or resolutions adopted by the authority, bear such date or dates, mature at such time or times, bear interest at such rate or rates, be in such denominations, be in such form, carry such registration privileges, be executed in such manner, be payable in lawful money of the United States, at such place or places within or without the state, and be subject to such terms of redemption or purchase prior to maturity as the resolutions or certificates may provide. If, for any reason, whether existing at the date of issue of any bonds or at the date of making or purchasing any loan or securities from the proceeds or after that date, the interest on any bonds is or becomes subject to federal income taxation, this shall not impair or affect the validity or the provisions made for the security of the bonds. The authority may make covenants and take or cause to be taken actions which are in its judgment necessary or desirable and possible to comply with conditions established by federal law or regulations for the exemption of interest on its obligations. The authority may refrain from compliance with those conditions if in its judgment this would serve the purposes and policies set forth in sections 41B.01 to 41B.23 with respect to any particular issue of bonds, unless this would violate covenants made by the authority. The bonds of the authority may be sold at public or private sale at a price or prices determined by the authority. The underwriting discount, spread, or commission paid or allowed to the underwriters of the bonds, however, must be an amount not in excess of the amount determined by the authority to be reasonable in the light of the risk assumed and the expenses of issuance, if any, required to be paid by the underwriters.