It was not until the 20th century that the north and south poles were reached by human beings.
A) Before the 20th century, there were no human beings living at the north and south poles.
B) Many attempts were made to reach the north and south poles, but the first successful one was in the 20th century. C) Before the 20th century, human beings didn't know that the north and south poles existed.
D) Man was only able to reach the north and south poles in the 20th century.
E) Until the 20th century, man lacked the equipment for a safe exploration of the north and south poles.​