Read the text about Wilbur and Orville Wright.

Wilbur and Orville Wright came from a family who valued education. Their father was a minister and had plenty of books in the family library for the boys to read. When Wilbur was eleven and Orville seven, their father bought them a toy helicopter that sparked their interest in flight. As adults, the brothers ran a printing press business and a bicycle business, then they became interested in flight again. They went to Kitty Hawk, North Carolina, which had excellent wind conditions and long, smooth hills. The brothers experimented with kites, gliders, and eventually their airplane. It flew on Dec. 17, 1903.

Which words indicate that this text is presented as a biography rather than as a memoir?

A.
airplane, it
B.
their, they
C.
boys, family
D.
father, minister