Certain Patients Can Develop "Tolerance" to Opioid Analgesics,which Is Indicated

Certain patients can develop "tolerance" to opioid analgesics,which is indicated by:

A) the onset of withdrawal symptoms if the drug is suddenly discontinued.
B) the fact that the patient may still crave the drug several years after he/she has ceased taking it.
C) the need to progressively increase the dose of the drug to achieve a therapeutic effect when the drug is used for prolonged periods.
D) all of the above
E) none of the above