When is the earliest flag-raising day in Tiananmen Square in a year?

From summer to morning in the northern hemisphere (around June 22), the sun shines directly on the Tropic of Cancer, the days in the northern hemisphere are long and the nights are short, and the Arctic Circle and its north are extremely day. During the winter solstice (about 65438+February 22nd), the sun shines directly on the Tropic of Capricorn, and the days in the northern hemisphere are short and the nights are long, and the Arctic Circle and its northern region are extremely night. At the equinox, the sun shines directly at the equator, and the whole world is as long as day and night. The closer to June 22nd, the earlier the flag will be raised. So this question chooses option C.