what is the difference between random assignment and random selection?

a. random assignment and random selection both refer to the sample selection of persons who will participate in a study

b. random assignment describes the sample procedure for including study participants and random selection is the process of placing participants to treatment or control conditions

c. random selection describes the sample procedure for including study participants and random assignment describes the way participants are placed into treatment and control conditions

d. random selection describes the control group and random assignment describes the treatment group