How to judge the weather system of A, B and C, and what is the basis?

A, according to the distribution and numerical value of isobar in the figure, it is not difficult to judge that the figure is a cyclone (low pressure), and rainy weather often occurs under its control. The typhoon in the southeast coastal provinces of China is formed by tropical cyclones, which does not conform to the meaning of the question; B, according to the moving direction of the cold and warm air mass in the picture, it can be judged that the picture is a schematic diagram of a warm front, and the precipitation intensity is small and lasts for a long time when the warm front crosses the border, and most of it is continuous precipitation, which does not meet the meaning of the question; C. According to the distribution and value of isobar in the figure, it is not difficult to judge that the figure is an anticyclone (high pressure), and sunny weather often appears under its control. The summer dry weather in the middle and lower reaches of the Yangtze River in China is caused by anticyclone, which does not conform to the meaning of the question. D. According to the moving direction of the cold and warm air mass in the picture, it can be judged that the picture is a schematic diagram of a cold front. When the cold front passes, the precipitation intensity is high, the duration is short, the wind is rainy and snowy, and the weather cools down. Rainstorms in summer in northern China, sandstorms in winter and spring in the north and cold waves in winter are all formed by cold fronts, so they are correct. Therefore, d is selected.