The majority of the climate region is covered in permafrost.
a. arid
b. tundra
c. highland
d. humid continental

Permafrost refers to  the part of ground (so not solid ice and not rocks) that are frozen over the whole year round. In the summer some uppermost layer might melt, but not the whole ground.

 Permafrost is found in the biome of tundra - and this is the correct answer (it can be found for example in Greenland)

I’m sorry i don’t know the answer