Please help me answer this I really need help

The western part of the United States and Canada is sparsely populated because there are mountains and deserts.

Explanation:

The first option is correct because the mountain chains are high, dominate the landscape, and on top of that, they also created suitable conditions for the development of deserts, so people naturally avoid these parts.

The second option is not correct because the western part of these countries doesn't have many cities, nor it is that large on farming.

The third option is not correct because there isn't a lack of resources, but the problem is the topography and climate.

The fourth option is not correct because this part doesn't fall into the so-called ''rustbelt''.

answer; the correct answer is chemical: