Unpleasant physical and/or psychological symptoms that occur when people stop taking a substance on which they have become physically and psychologically dependent is:

A. dependency Dependency is the state of being reliant on a substance, not the symptoms that occur when it’s removed. B. cross-tolerance This is when tolerance to one drug produces tolerance to another (usually in the same class), not related to stopping use. C. tolerance Tolerance is needing more of a substance to get the same effect, not about stopping use. D. withdrawal Withdrawal refers to the physical and psychological symptoms that occur when someone stops using a substance after becoming dependent.