The answer is C. fire barrier
The answer would be b. an appeal to fear.
I think its Puppet i hope its right please forgive me if it isnt.
Answer:
hope this helps
Explanation:
The electric furnace (1889) It was “the only means for commercially producing Carborundum (the hardest of all manufactured substances).” The electric furnace also converted aluminum “from a merely precious to very useful metal” (by reducing it’s price 98 percent), and was “radically transforming the steel industry.