Why Shouldn't a Laboratory Technician Conclude That a Potential New

Why shouldn't a laboratory technician conclude that a potential new employee might be abusing opioids if morphine-6-glucoronide is found in a sample?

A) This is a metabolite produced from many opioids including codeine, which may have been prescribed for a severe cough.
B) The compound is made naturally in the body, particularly in those who are highly physically active.
C) The metabolite is normally produced with first using an illicit opioid, indicating recreational use rather than abuse.
D) The metabolite remains in the body for weeks, indicating that the employee may not be a current user.