The parents of 2-year-old Joshua are frustrated with his screaming when he wants something. According to Skinner, which statement would be the BEST advice to give Joshua's parents if they wish to stop Joshua's screaming? A) Always give Joshua what he wants when he screams B) Give Joshua what he wants whether or not he screams C) Never give Joshua what he wants when he screams D) Sometimes give Joshua what he wants when he screams, and sometimes refuse to give him what he wants when he screams