Read this excerpt from White Fang. It was during this period that he might have harkened to the memories of the lair and the stream and run back to the Wild. But the memory of his mother held him. As the hunting man-animals went out and came back, so she would come back to the village some time. So he remained in his bondage waiting for her.

Which best describes the force that motivates White Fang’s choice in the excerpt?

an internal force based on instinct
an internal force based on feeling
an external force based on setting
an external force based on conflict