Answer:
The third box from the left hand side
Explanation:
A sleet is a form of precipitation in which water reaches the surface in a frozen state or in form of ice.
Sleets are common occurences in the temperate region.
If we trace the material circled by the third box from the origin, we would be able to provide an explanation that perfectly fits how sleets forms.
Water in the cloud is in a supersaturated frozen form. As the water encounters warm air, the freeze melts to water. As the water comes down and approaches the surface, it encounters a cold air front which immediately freezes the melt water. This is the sleet that reaches the surface.
The first and second box from the left hand side is rain droplet. The last box is snow flakes.
