can you help me this

1. A. How does one determine if electric circuit theory can be applied to a specific problem? How does one determine if electromagnetic theory can be applied to a specific problem? B. If renewable hydro power is bought by local utilities from Canadian sources located about 1300 miles north of LA, can circuit theory be used to analyze this power distribution circuit? Explain why or why not and show any calculations. C. Explain what the passive sign convention means. Using this convention, what would be the sign of the power from the Canadian sources and what would be the sign of the power going to the utility customers in LA