The earliest solar terms are

The first step is to investigate literary knowledge.

The second step, "Less frost at the end of the year, vegetation in the spring" comes from beginning of spring Encounter by Zhang Wei in the Song Dynasty, which means that less frost at the end of the year leads to vegetation in the spring. At present, I only feel full of vitality, and the east wind blows the green waves on the water surface. According to the twenty-four solar terms, Song: Spring rains shake the spring and clear the valley days, and summer is full of summer. Autumn dew, autumn frost, little snow in winter and cold in winter. Therefore, the 24 solar terms described belong to beginning of spring. The earliest solar term in a year is beginning of spring, so choose option A. ..