单选题 His ______ remarks are often embarrassing because of their frankness.

【正确答案】 C
【答案解析】(ingenuous坦率的,天真的)。句意为:由于坦率,他天真的话往往令人尴尬。A.sarcastic讽刺的;B.urbane有礼貌的;D.sadistic虐待狂的。