How Would You Explain That Emotional Learning of an Addiction

How would you explain that emotional learning of an addiction has a biological, not merely moral or sociological, basis?

A) The mesolimbic dopamine system prevents the amygdala from storing memories, resulting in permanent changes in the brain function of addicts.
B) Repeated drug use leads to addiction in some people because the good feelings they get reset the MFB in the amygdala, where memories are stored.
C) Chronic exposure to a drug sets up memories in the amygdala and can, in some people, yield changes in brain function that produce a learned response.
D) Chromic drug use and the good feelings associated with taking it cannot reset dopamine levels in an addict's MFB and therefore produce a learned response.