The correct answer is: A. a, the, the
R. Peary was a famous American polar traveler. He was the first to reach the North Pole in 1909.
The article “a” is used before a common noun that is not specific. In this case, “polar traveler” is a common noun that could refer to any polar traveler.
The article “the” is used before a specific noun. In this case, “North Pole” is a specific noun that refers to a particular place.
There is no article before “1909” because it is a year. Years are not preceded by articles.