Which of the Following Would Be a Nonequivalent Comparison Groups

Which of the following would be a nonequivalent comparison groups design?

A) Compare two different sites that seem comparable except for the type of intervention, program, or policy provided in each.
B) Compare the degree of change achieved by service recipients and clients on a waitlist for those services.
C) Refer clients to a new treatment or to routine treatment. depending on caseload openings at the time of referral.
D) All of the above.