To answer this question, let's examine the given options and the factors that determine whether children need to move on snow for going to school.

a) Northern Hills:
In regions with hilly terrain and a cold climate, such as the Northern Hills, it is common for children to encounter snowfall during the winter season. The presence of snow can make it challenging for children to commute to school without moving on snow.

b) Assam:
Assam, located in northeastern India, has a relatively warmer climate compared to the Northern Hills. Snowfall is not a common occurrence in this region. Therefore, children in Assam do not need to move on snow for going to school.

c) Uttarakhand:
Uttarakhand is a state in northern India that includes parts of the Himalayas. Similar to the Northern Hills, Uttarakhand experiences snowfall in certain areas during the winter season. Hence, it is likely that children in Uttarakhand may need to move on snow when going to school.

d) Gujarat:
Gujarat, located in western India, has a predominantly hot and dry climate. Snowfall is extremely rare in this region. Consequently, children in Gujarat do not have to move on snow for going to school.

From the given options, it is clear that the correct answer is option 'a) Northern Hills'. The Northern Hills, which include states like Himachal Pradesh, Uttarakhand, and Jammu and Kashmir, are known for their cold climate and snowfall during winter. Therefore, children in this region often have to navigate through snow to reach their schools.

Snown