Read the light map of the earth (the shaded part is night, the blank part is day, → indicates sunshine), and complete 1 ~ 24: The solar terms in the northern hemisphere on that day are () A.

When the earth revolves around the sun, the axis of the earth forms a fixed inclination angle of 66.5 with the orbital plane, so that the direct point of the sun's rays regularly moves between the Tropic of Cancer and the Tropic of Cancer in a year. Looking at the map, we can see that the latitude of direct sunlight at this time is the tropic of cancer, and when the sun rays directly reach the tropic of cancer, it is the summer solstice in the northern hemisphere, and the date is around June 22.

So choose: a.