What is one advantage the United States has over Canada for maintaining a diversified economy?

Question

The U.S. has a greater gold resource

The U.S. has a greater labor resource

The U.S. has a greater per capita of fresh water

The U.S. has a greater land resource***

Answer 1

http://www.unitednorthamerica.org/simdiff.htm

Answer 2

thx

Answer 3

So which one is it