I'm pretty sure the 8 marker had little to do with the AC vs. DC argument of Westinghouse and Edison; the stimulus provided did mention it, however the question did not asking anything about it. Hopefully you guys weren't tricked and actually wrote a detailed analysis on how and why AC creates eddy currents (alternating current, changes in flux, induces circular current due to Lenz's Law), the effects of an eddy current (heat), the uses eddy currents have (electronic breaking, induction cooktops), the problems it faces (in reducing efficiency of transformers) and possible methods of resolving these problems (lamination). My friends have said they wrote a good essay about Westinghouse vs. Edison, and I pretty much facepalmed. Hopefully you guys didn't make the same mistake.