B. chief examiner.
A chief examiner would be someone or something else unrelated entirely. Perhaps a police chief or a medical examiner are the closest to a "chief examiner" anything.
Answer: Id say its D Royal inspector hopfully Im right
Uncle toms cabin i am pretty sure
Actually the real answer is the second and first world war pouring money into the us economy for output. If that is not an option it would be the invention of the steam engine and the 1800's locomotive industry.