Which of the following states has a natural boundary?
A. New Mexico
B. Colorado
C. Nevada
D. California
Incorrect. All four borders of New Mexico are man-made, imaginary lines, which is political.
Incorrect. All four borders of Colorado are man-made, imaginary lines, which is political.
Incorrect. All borders of Nevada are man-made, imaginary lines, which is political.
Correct! The western boundary of California is the Pacific Ocean, a natural border.