Which of the following is not a derivative of opium?

a. xanax
b. hydrocodone
c. heroin
d. methadone

Opium derivatives are also called opiates; and can include illicit and non-illicit drugs such a Hydrocodone (Pain reliever medication), Heroin (illegal street drug), and Methadone (is used commonly to get patients of Oxy's). Xanax is a a different type of pain medication called a Benzo or Benzodiazipine. 

A. Xanax , because on a drug test a xanax qualifies as a benzodiazepine , like Klonopin , Valium , Ativan , etc.

Cotton with iron probably