Henry does write his report very carefully, but I find that ______ of his two solutions is correct.
【正确答案】 D
【答案解析】由转折词but可推出，“我”不赞同亨利提出的两个解决方案，可首先排除A、C；另外主语是all of his solutions／both his solutions时不能用is。none是指“三者或三者以上都不”，neither指“两者都不”，这里答案应为D。