The lunar calendar used in China is a () calendar, in which the 24 solar terms are based on the period of revolution of the earth and belong to the () component.

The answer is D. Qingming is one of the 24 solar terms in the lunar calendar, which is divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun). Therefore, options a and b are incorrect. The first solar term in Tomb-Sweeping Day is the vernal equinox. At the vernal equinox, the sun shines directly at the equator, and then the direct point gradually moves northward, so the direct point of the sun is in the northern hemisphere at Qingming, and the C option is wrong. At the vernal equinox, day and night are equal, then the day becomes longer and the night becomes shorter until the summer solstice. The solstice in summer has the longest day and the shortest night. Therefore, the d option is correct.