28.(A)Nerli conducted a randomized clinical trial to investigate the efficacy of a brief outpatient rehabilitation program using a cognitive behavioral approach for PCC.(B) Over the past few decades, substantial evidence has amassed for the efficacy of CBT for symptoms in the context of somatic conditions, including chronic fatigue syndrome.(C) Theoretically, given that physiologic, cognitive, behavioral, and social processes are correlated, it follows that change in one system will bring about a change in the others. (D)So far, there should be no other explanation for the symptoms that may substantially impact daily activities.