The statement that best explains Wright's assertion that he and his father "were forever strangers" is:
Wright is stating that he is emotionally disconnected from his father.
Whenever two persons are strangers to each other. They are ignorant of the other person's thoughts and emotions. When Wright says that he and his father were forever strangers. Wright is highlighting that he was unaware and ignorant to who his father was. Also, one can conclude that his father probably felt the same way.