Answer: a. dsm-5
Explanation: The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is used In the United States as the principal authority for psychiatric diagnoses, treatment recommendations and payment by health care providers by the DSM classification.
This fifth edition, that came out in 2013 and is still being used till now has significant practical importance, and it was published by American Psychiatric Association (APA)
This is where Rennie had to check to get the exact code of her mental ailment.