Cold front crossing, strong wind cooling, rain and snow

② Located near the center of low pressure, the weather system is frontal cyclone. In the horizontal direction of the cyclone in the northern hemisphere, the airflow flows counterclockwise from the periphery to the center. Judging from the coincidence of the central planes in the figure, ② it is about to cross the border, and there will be strong winds and rain and snow when the cold front crosses the border.

So choose: a.