【正确答案】 D

【答案解析】根据最后一段中主人公的心理活动“He asked himself what else could he have done. He could not have lived with her openly. He had done what seemed to him best. Now that she was gone he understood how lonely her life must have been, sitting night after night alone in that room”，可以看出主人公“非常后悔”自己过去的所作所为，正确答案应为[D]。另外，angry和irritable基本上可以算是一对形容词，可以排除[A]和[C]。