The condition in which a drug user's body becomes so accustomed to a particular drug that it can only function normally if the drug is present is known as

The condition in which a person's body is so much used to a drug, that it works only in the presence of the drug, is known as dependence on the drug. This happens due to the addiction of the body towards the drug and the the drug is a part of many metabolic athways of the body. A basic level of drug is therefore required for normal functioning of the body. 

The answer is b im not sure 

The answer for your problem would be a. 7