Answer:
c. Matching subjects in the experimental group to those in the comparison group
Step-by-step explanation:
Nonequivalent groups design: In psychological research, the term "nonequivalent groups design" is described as one of the "quasi-experimental research designs" whereby a dependent variable is being measured by following a specific treatment in a single group. It is being used to estimate or analyze the "relative effects" of two or more than two treatment conditions i.e, only two different treatments are being compared.