The correct description of the weather on that day is () A. All-day rainstorm B. All-day sunny C. Sunny in the morning and cloudy in the afternoon D. Cloudy in the afternoon.

According to the map, the distribution law of solar radiation reaching the ground in this area is as follows: the solar radiation is small at 4: 00- 12: 00 in the morning and large at 12: 00-20: 00; The small amount of solar radiation reaching the ground in the morning should be due to the large reflection of the clouds on the sun, while the large amount of solar radiation reaching the ground in the afternoon should be due to the small weakening effect of the atmosphere on solar radiation, which should be sunny; So it's supposed to be cloudy in the morning and sunny in the afternoon. A, b, c, error, d is right.