Mark conducts a study for his research methods class to determine if consuming caffeine causes people to perform better on cognitive tasks. In his study, he gives half of his participants a glass of water and half of his participants a glass of cola, and then has them attempt to solve 15 math problems. He finds that people who drink caffeine beforehand solve more math problems than those who drink water beforehand. Refer to Research Study 14.1 to answer the following three questions. Mark decides to conduct a conceptual replication. Which of the following could be in the study to make it this type of replication? B
a. Having participants complete 10 math problems instead of 15
b. Having participants drink a caffeinated energy drink rather than a caffeinated cola
c. Measuring a different group of participants
d. Measuring the same participants one week later