If prisoners were mentally ill/drug abusers, do we really want their organs?
use websites and actual studies.

This depends on which organs we're talking about. A mentally ill person or a drug abuser can still have completely healthy lungs, depending on the type of drugs the drug user was taking. The same goes for the heart and other internal organs. If the lifestyle of the mentally ill person or the drug abuser were such that their internal organs suffered, then the answer would be no. 

The answer is 3) taking ownership of the decision