The Solomon four-group design involves a. two trained groups measured before and after a training program.

The Solomon four-group design involves

a. two trained groups measured before and after a training program.

b. two control groups measured after a training program, and two trained groups  measured before and after training.

c. a training group and a control group measured before and after training, and a training and control group measured after training.

d. three training groups and one control group all measured before and after the training.