Which of the Following Statements About the Role of Genetics

Which of the following statements about the role of genetics as a risk factor for eating disorders is true?

A) Although the findings to date are mixed, the evidence does indicate that a susceptibility to eating disorders may be inherited along with a diathesis for other psychological conditions.
B) The lack of adoption studies has made it impossible to determine the heritability of eating disorders.
C) While the gene underlying the restrictive type of anorexia nervosa has been identified, the role of genes in the development of other forms of eating disorders is not clear.
D) Due to the complex nature of eating disorders and the probability that multiple genes contribute to their development, a role for genes in such disorders has yet to be established.