Test analysis: this question mainly examines literary common sense. Poet sage is a kind of praise to Du Fu by later generations. Among the four options, only option A comes from Du Fu's Spring Watch, b and c come from Li Bai's Looking at Lushan Waterfall and Farewell to Meng Haoran on the Way to Yangzhou respectively, and c comes from Bai Juyi's Biegu Cao. So the answer is a.