The choices for this question are:
a. Regions are always unchanging and distinct in nature.
b. Different perceptions of a region can make that region less defined.
c. A region is an area on Earth that is defined by certain unifying characteristics.
d. Regions are based on human perceptions.
Answer: d. Regions are based on human perceptions
The geographic theme of region considers the geographical location of an area which is called a region. Thus, regions are not merely formed through subjective perceptions but through all the other statements combined except d.