What is a good control group for a research study on people with eating disorders?

What is a good control group for a research study on people with eating disorders?
 
  A) A group that is drawn from the sample of people with eating disorders.
  B) People who used to have eating disorders but no longer say they do.
  C) People who have an eating disorder and a wide range of educational backgrounds.
  D) A group that is comparable to those with eating disorders except they eat normally.

Question 2

Feeding and Eating Disorders also include which of the following disorders?
 
  a) Pica
  b) Rumination Disorders
  c) Anxiety Disorders
  d) Both a and b

Question 3

The DSM-5categorizes eating disorders as:
 
  a) Feeding and Eating Disorders
  b) Addictive Disorders
  c) Anxiety Disorders
  d) Obsessive Disorders

Question 4

To determine whether certain characteristics are true of people in general, and not just of people with
  mental disorders, it is important to use
 
  A) a representative sample of individuals with the disorder.
  B) an experimental design.
  C) a criterion group.
  D) a control group.