Why Is Pharmacogenetics/pharmacogenomics of Particular Interest in Treating Patients with Psychiatric/mental

Why is pharmacogenetics/pharmacogenomics of particular interest in treating patients with psychiatric/mental health problems?

A) Psychiatric medications may be effective in only a small group of patients.
B) Genetics restricts patients to only one drug in each classification.
C) Most psychiatric illnesses are single-gene disorders with predictable drug responses.
D) Psychotropic medications have few side effects.