State whether or not each of the following is correct and explain your reasoning. If the quotation is incorrect, provide a corrected statement.
a. "We Mexicans can never compete profitably with the Northern colossus. Her factories are too efficient, she has too many computers and machine tools, and her engineering skills are too advanced.
We need tariffs, or we can export nothing!"
b. "If American workers are subjected to the unbridled competition of cheap Mexican labor, our real wages must necessarily fall drastically."
c. "The principle of comparative advantage applies equally well to families, cities, and states as it does to nations and continents."
d. The quotation from Ross Perot on page 356.