Which of the following is NOT a prohibited screening criterion?

The correct answer revolves around the understanding of acceptable screening practices within the multifamily housing context. Requiring that an applicant not have unacceptable credit ratings is not a prohibited screening criterion because it falls within the reasonable practices for assessing an applicant's financial stability and ability to pay rent. Many landlords and property management companies use credit checks as a standard measure to evaluate potential tenants, as a poor credit history can indicate a higher risk of defaulting on rental payments.

In contrast, the other choices represent practices that can be deemed discriminatory or inappropriate. For example, requiring a donation or contribution as a condition of admission is unethical and often illegal, as it can exclude applicants based on their financial status. Similarly, requiring an applicant to undergo medical testing would be considered invasive and could violate privacy laws and fair housing regulations. Lastly, specific minimum income requirements, while common, can also create barriers for certain groups if not implemented thoughtfully, especially when not aligned with fair housing guidelines.

Overall, assessing an applicant's credit rating is a standard and accepted part of the tenant screening process that helps protect landlords while also ensuring that applicants have the financial capability to meet their rental obligations.