You find a spool of pure copper wire while snooping through your brother's purse. The wire has a diameter of 0.3 millimeter and a length of 200 meters. A) Derive a formula for the resistance of the spool as a function of temperature. B) Estimate the resistance of the spool at 0 C and 100 C. C) if this wire is held at 25 C and stressed to 95% of its yield stress, estimate its resistance.