42. According to the passage, which of the following statements about the patients of PTSD is true? (A) They have vivid memories of events that objectively happened. (B) The longer they stay in the I.C.U., the more likely they are to suffer from PTSD. (C) More than three million I.C.U. patients suffer from PTSD annually in America. (D) Many of them are screened for mental disorder when leaving the I.C.U.