Li Yanqin Monument was written in the 14th year of Dali (779) by Zhenqing [1]. Regular script, inscription. Residual stone 175×90×22 cm. The monument is engraved on four sides and has books on three sides. Beiyang 19 lines, Yin Bei 20 lines, 38 words each. There are five lines on the left, each with 37 words. On the right side of the first half of the Song Dynasty, the poet engraved the words "Suddenly surprised and forced to dawn, snow washed the haze" and wrote an inscription by Song Bolu of the Republic of China. The existing anbeilin is the first batch of steles collected by the Palace Museum in Beijing. Yan's stele body shows a tall and straight spirit, while Ma Gu Xian Tan Ji shows an ethereal and far-reaching charm, which can be called two peaks.
Yan Zhenqing (709-784, Yi Shuo 709-785), born in Wannian, Tang Jingzhao (now Xi, Shaanxi), was a calligrapher in the Tang Dynasty in China. An outstanding calligrapher in the middle Tang Dynasty. His "Yan Ti" regular script, together with Zhao Mengfu, Liu Gongquan and Ou Yangxun, is also called "the four masters of regular script".
So it should be Yan Zhenqing's works in his later years. Option d