Susan runs a factory in Texas that produces heaters. she has done a cost analysis on production and found that it would cost her $5.40 US to buy the input materials in the United States (per heater); 5.4 pesos (Mexican currency) in Mexico (per heater); and $6.00 Canadian (in Canada). All Transport costs are included in the input cost. Assume the exchange rate for the peso to be $0.80 of $1.00 US, and that $1.00 Canadian is $0.90 US what production structure should Susan's company use?

A. import materials from Canada

B. import materials from Mexico

C. export materials to Mexico

D. use materials from the US