Use the Following to Answer Questions

Use the following to answer questions :
Scenario II
It is challenging to conclusively demonstrate the effectiveness of treatments for psychological disorders.Although treatments may appear to work,their apparent effectiveness could be due to a number of other factors,termed treatment illusions.Treatments may appear effective due to natural improvement unrelated to the treatment,placebo effects in which the apparent effectiveness of a treatment is due to the expectancy of its effectiveness,and reconstructive memory in which persons remember their symptoms prior to treatment as more severe than they were.
-(Scenario II) A research psychiatrist is studying the effectiveness of a new drug to treat insomnia.Patients with the disorder are studied in a sleep laboratory for 1 week before the study begins,and the time to fall asleep and the amount of time in each stage of sleep are recorded.Then they are randomly assigned to either the treatment group (which receives a drug) or the placebo group (which receives a placebo pill) and studied in the sleep laboratory for another week.At the end of the study,objective measures improved in both groups but more so in the group that received the treatment.The researcher concludes that the drug is effective at treating insomnia,but a skeptic might wonder if the results are due to natural improvement.The researcher would respond that:

A) insomnia rarely goes away on its own.
B) the study is indeed fatally flawed and a second control group that receives absolutely nothing but is studied over the course of the entire 2 weeks is needed.
C) the meticulous sleep logs kept pre- and posttreatment rule out this possibility.
D) if the treatment effect was due entirely to natural improvement,there would not be an observed difference between the treatment and placebo groups.