A Study Compared Controlled Opiate Users with Narcotic Addicts and Found

A study compared controlled opiate users with narcotic addicts and found that the former differed from the latter in:

A) the type of narcotic used-for instance, Darvon or codeine versus heroin.
B) the route of administration-snorting versus shooting.
C) personal acquaintance with other users who suffered overdoses.
D) the frequency of use-that is, less than once a day versus more than once a day.
E) none of the above.