'Climatic variations' and 'Human activities' can be regarded as the two main causes of desertification. removal of the natural vegetation cover(by taking too much fuel wood), agricultural activities in the vulnerable ecosystems of arid and semi-arid areas, which are thus strained beyond their capacity.
Forestry and mining
are not industries that are based on importing good. So A is not the answer
are not both Agricultural, so b is not the answer
are industries that exist in the west. so d is not the answer
The only answer that makes sense is C. Industries in the west based on available natural resources.