Allen finds himself addicted to an illegal drug. though he considers his crime harmless, his offense is considered a crime against a. himself b. society c. drugs d. family

I think it's a because they are talking about himself

I believe it would be himself. He is doing harm to himself, but he is (as far as we know) not doing bodily harm to anyone else. Much like suicide, this can be considered manslaughter if he overdoses.