True or false the narrator, by choosing to tell the story in one way or another, can become a kind of character in it.

The answer to this question is true. Sometimes the narrator can also be a one of the characters in a story or can even be the main character in a story. A narrator is the one who tells the story. He/she is the voice that the author chose to tell the story. The narrator can be someone from the story. Normally, that character's point of view, characteristics and personality is the one used by the author to convey the message as the narrator of the story. 

Santiago's points of view. strength and opportunity