Final answer:
Refusing to rent to someone who does not meet economic qualifications
Step-by-step explanation:
The Fair Housing Act of 1968 (also known as the Civil Rights Act of 1968) prohibits discrimination in the sale or rental of housing. Under this act, it is a violation to refuse to rent to someone who does not meet economic qualifications. Therefore, the correct answer is D. Refusing to rent to someone who does not meet economic qualifications is a violation of the Fair Housing act.