The Board of Trustees may designate not more than five companies from which annuity contracts are to be purchased under the program. The Board of Trustees shall approve the form and contents of annuity contracts to be offered by a company that is designated by the Board of Trustees under subsection (a) of this section. In making the designation and giving approval under this section, the Board of Trustees shall consider: the nature and extent of the rights and benefits to be provided by the annuity contracts for participating employees and their beneficiaries; the relation of those rights and benefits to the amount of contributions to be made; the suitability of the rights and benefits to the needs of the participating employees and the interests of the employing institutions in the recruitment and retention of participating employees; the ability of the company to provide for suitable rights and benefits under the annuity contracts; the selection of annuity contracts offered by the company; the financial stability of the company and whether the company meets minimum financial criteria, if any, including a minimum net worth requirement, if any, established by the Board of Trustees; and the effect of any fees, commissions, or other charges imposed or collected in connection with an annuity contract.