Reusing or sharing needles, really anything that can be spread through blood and drugs.. i hope this helps and sorry its so brief.
Answer:
D. Bile
Another thing to note as well is that it also produces Dopamime which is how you get adicted to the substance and makes you feel good. But not in a good way at all.
I'd suppose that the answer is most likely: c. Self-monitoring.
(I really hope this is of some help to you)
I am an organ donor. I believe that if my body can make someone survive an illness (cancer/leukemia) or recover from a condition such as blindness or a missing limb, then It is my duty to allow for that to happen. When I die, my soul will go on but my body will just rot so why not let someone use up what they can. I am especially strong in my opinion when dealing with pediatric illnesses. If a child needs my lungs or my kidneys, they should take them and live a long life. After I pass, they are useless to me!