The correct answer is: A. semi-arid
Thorn forests are found in semi-arid regions, which are areas that receive less than 250 mm of rain per year. These forests are characterized by their dense growth of thorny trees and shrubs. The trees and shrubs in thorn forests are adapted to the dry climate by having deep roots that can reach water deep underground. They also have thick, waxy leaves that help to reduce water loss.
Option B is incorrect because high rainfall areas are not typically home to thorn forests. Thorn forests are found in areas that receive less than 250 mm of rain per year.
Option C is incorrect because low temperature areas are not typically home to thorn forests. Thorn forests are found in areas that have a warm climate.
Option D is incorrect because frozen areas are not typically home to thorn forests. Thorn forests are found in areas that have a warm climate.