At 7: 26 a.m. on a certain day, a grand flag-raising ceremony was held in Tiananmen Square. This day is most likely () A. New Year's Day B. Tomb-Sweeping Day C. Labor.

When the sun shines directly at the equator, it is the vernal equinox (the date is around March 2 1 day) or the autumn equinox (the date is around September 23) in the northern hemisphere. At this time, the length of day and night in the world is: day and night are equal; When the sun shines directly on the Tropic of Cancer, it is the summer solstice in the northern hemisphere (the date is around June 22), and the length of day and night in the northern hemisphere is the longest in the day and the shortest in the night; When the sun directly hits the tropic of Capricorn, it is the winter solstice in the northern hemisphere (the date is around 65438+February 22). At this time, the length of day and night in the northern hemisphere is: the shortest day and the longest night.

Among the four solar terms in the option, New Year's Day is 65438+1 October1,which is closest to the winter solstice, so this day is the shortest of the four solar terms. Tomb-Sweeping Day is in early April, and Labor Day is 1 in May. Between the vernal equinox and the summer solstice, the days are long and the nights are short. The National Day is 65438+ 10/month 1, which is close to the autumnal equinox, that is, close to the length of day and night.

According to the topic, a grand flag-raising ceremony was held at Tiananmen Square in Beijing at 7: 26 am, which means that the sun rises at 7: 26 am (the time from noon to 12 is the same as that from noon to sunset), which means that the day is about 9 hours long and the night is about 15 hours long.

So choose: a.