My friend sustained brain damage from a percussive blow from a nearby shotgun blast in a hunting accident. after recovering from a coma, he came back to school and seemed normal for 4 months, after which he began to show disordered behavior, learning difficulties, and rapid mood changes. he developed a chronic tobacco habit. this habit was probably related to
a. attempt at self medication to activate noradrenaline receptors
b. attempt at self medication to activate dopamine receptors
c. attempt at self medication to activate acetylcholine receptors
d. all of the above
e. none of the above