In my opinion, the correct answer is B. calm. It is not light or uncaring - it is obvious that the narrator understands and sympathises with the pilot. But it is not hysterical either. Here is an excerpt that illustrates the calmness, but also the sympathy and understanding. It describes the pilot's emotional state when he realizes that there is a stowaway. "He let his eyes rest on the narrow white door of the closet. There, just inside, another man lived and breathed and was beginning to feel assured that discovery of his presence would now be too late for the pilot to alter the situation. It was too late; for the man behind the door it was far later than he thought and in a way he would find it terrible to believe."
