Which is NOT a reason why nations engage in trade?

a. The distribution of natural, human, and capital resourcesamong nations is uneven.

b. Efficient production of various goods requires differenttechnologies and not all nations have the same level oftechnological expertise.

c. To protect national security

d. Products are differentiated as to quality and otherattributes, and some people may prefer certain goods imported fromabroad rather than similar goods produced domestically.