The Nonequivalent Comparison Group Design Can Yield Several Possible Outcomes

The nonequivalent comparison group design can yield several possible outcomes. A possible outcome of the non-equivalent comparison group design is that the control group scores higher than the experimental group on the pretest and posttest but the experimental group improves more on posttesting. This could reflect the fact that the independent variable had an effect on the experimental group. It could also reflect

A) an unreliable dependent measure.
B) the fact that the control group experienced less of the independent variable than the experimental group did.
C) regression-artifact effect if the experimental group had been selected for their low initial scores.
D) a selection-maturation effect if the experimental group had been selected for their older age.