I think it is the 3rd answer choice.
<span>There are 19 States that are completely north of 40 degrees north latitude or otherwise known as the 40th parallel. The states that are north of the 40th parallel are as follows from west to east; Washington, Oregon, Idaho, Montana, Wyoming, North Dakota, South Dakota, Nebraska, Minnesota, Iowa, Wisconsin, Michigan, New York, Connecticut, Rhode Island, Massachusetts, Vermont, New Hampshire and Maine.</span>
Answer:
The most common geographic boundary is the physical boundary.
Explanation:
Rivers, mountains, lakes, deserts are all physical boundaries.
The Mississippi River is a physical boundary between many countries that trespasses, including Iowa and Illinois, Louisiana, and Mississippi.
Pyrenees Mountains are also the geographic boundary between France and Italy.
