What Elisha Otis invented?

Answer: Option A

In 1853, American inventor Elisha Otis demonstrated a freight elevator equipped with a safety device to prevent falling in case a supporting cable should break. This increased public confidence in such devices. Otis established a company for manufacturing elevators and patented (1861) a steam elevator.
Many people think that he invented the elevator, but the truth is, he invented the elevator brake. He also invented the railway safety brake.