What sparked the development of the second revolution

a the development of a better way to produce iron cheaply

b a better way of producing steam and gasoline, and new fibers for textiles

c petroleum, electricity, and an inexpensive way to produce steel

For the answer to the question above, the Second Industrial Revolution witnessed the expansion of electricity, petroleum, and steel. So believe the answer is C petroleum,electricity,and an inexpensive way to produce steel.
I hope my answer helped you. Have a nice day!