A circuit diagram depicts a vertical zig-zag line connected between two wires. Which reasoning most strongly supports the conclusion that the symbol represents a resistor even though it is rotated?
a) Vertical elements in a schematic indicate energy storage, so the symbol must represent a capacitor rather than a resistor
b) Components drawn vertically generally symbolize variable elements; therefore a vertical zig-zag must be a variable resistor
c) Standard resistor symbols are orientation independent because their electrical function is unaffected by rotation
d) The zig-zag pattern means the current alternates direction through the component, identifying it as an AC source