If an Officer, While Conducting a Pat-Down Search Under Terry

If an officer, while conducting a pat-down search under Terry, feels an object that he or she believes is an illegal narcotic, how should the officer proceed?

A) The officer should continue the pat-down for weapons and, if a weapon is found, the officer can expand the search to explore whether the object is narcotics.
B) The officer must limit his search to the parameters of Terry unless he or she is able to establish probable cause to believe that the object is an illegal narcotic.
C) The officer should detain the suspect until he or she can obtain a search warrant authorizing a more extensive search of the individual.
D) The officer can expand his or her search to parameters to those consistent with a search incident to an arrest.