Andre is trying to abstain from using drugs. which factor is most likely to result in his relapse? a. the fact that he was a light user b. becoming concerned about his academic success in college c. lack of a social support network d. having a demanding job that requires significant involvement

I believe the correct answer is C. lack of social support network.
Andre cannot do this on his own - because he was a drug addict and now he wants to stop using drugs, he needs a support group which will be there for him to help him through the process. If he doesn't have such a group, or friends/family to be there for him, there is a high chance that he will relapse.