Final answer:
Harlingen can be found in the region of South Texas.This area is known for its warm climate, close proximity to the border with Mexico, and for being an important agricultural and industrial region.
Step-by-step explanation:
The answer to the question is d) South Texas.
Harlingen is a city located in the southernmost part of Texas, close to the United States-Mexico border. Therefore, it falls under the region known as South Texas. You would find Harlingen in the South Texas region. Harlingen is a city in the Rio Grande Valley which is in the southern part of Texas. This area is known for its warm climate, close proximity to the border with Mexico, and for being an important agricultural and industrial region.