Why Was Electricity the Most Important Power Source for the Second

Why was electricity the most important power source for the second industrial revolution?

A) Britain was rich in coal, so it did not have to rely on foreign supplies to power its factories.
B) Electrical power generation plants were pollution free.
C) Factories could be located near concentrations of workers and production costs were lower.
D) Some new industries, such as the iron industry, were dependent solely on electricity.