The correct answer is B. Great Plains
Step-by-step explanation:
Amarillo and Lubbock are two cities in the north of Texas state, which is located to the South and Center of the U.S. Moreover, in terms of geographical regions these two cities and most of Texas belong to a region known as the Great Plains.
This region is located in the center of the country and extends from the northern border of Canada to the South ending in Texas. Additionally, due to its central location, this region covers states such as Montana, Kansas, Nebraska, and most Texas. According to this, the correct answer is the Great Plains.