He sent a letter to government officials in Washington,----a revolutionary invention.A publishing B speaking C saying D announcing

He sent a letter to government officials in Washington,----a revolutionary invention.A publishing B speaking C saying D announcing
He sent a letter to government officials in Washington,----a revolutionary invention.
A publishing B speaking C saying D announcing

He sent a letter to government officials in Washington,----a revolutionary invention.A publishing B speaking C saying D announcing
答案：D
A发表,发布,一般指文章或其他文字性的东西
B,C很明显不对
D宣布,宣称