Dr Dormeur Studies Sleep and Sleep Disorders

Dr. Dormeur studies sleep and sleep disorders. She is curious as to whether technology exposure before bedtime causes people to fall asleep more slowly. She recruits a sample of 60 middle-aged women from a local church who reported no history of sleep problems. She creates three conditions. All participants come to the sleep lab for three nights in a row and experience all three conditions. In the first condition (A) , participants were asked to play an online game (Candy Crush) on an iPad for 10 minutes prior to going to bed. In the second condition (B) , participants were asked to read an article using an iPad that discussed tricks and tips for improving one's score on Candy Crush (which took about 10 minutes) . In the third condition (C) , participants were asked to read a newspaper article about the inventor of Candy Crush (which took about 10 minutes) . With the use of an electroencephalograph (EEG) , the researcher measures how long it takes participants to fall asleep.
Which of the following designs is Dr. Dormeur using?

A) Pretest/posttest design
B) Concurrent-measures design
C) Repeated-measures design
D) Posttest-only design