A researcher is conducting research on using technology in teaching. The researcher has two groups. The first group receives instruction via a PowerPoint presentation that is online. The second group attends a class and receives instruction from a teacher face to face. The researcher classifies the students based on when they volunteer for the study. The first 50 students who volunteer receive online instruction. The next 50 receive instruction by attending a class with a teacher. With respect to this study, we could identify that: a. This study is poor because the researcher used random sampling. b. This study is poor because the researcher did not use random sampling. c. This study is good due to the equal sample size in each group. d. This study is good because we have minimized sampling error.