单选题 Even though he knew that his mother had been ill, he did not have the propriety to write her.
【正确答案】 A
【答案解析】解析：句意：尽管他知道母亲一直在生病，但他还是没有按照礼节给她写信慰问。“propriety”意为礼貌、礼节。A选项意为礼貌、体面，因此为正确答案。