How does Campbell's statement about the transition from childhood to adulthood support his claim that the hero's journey is a universal experience?
a) It emphasizes the idea that the hero's journey involves overcoming fear and taking on responsibility
b) It suggests that the hero's journey includes a literal death and rebirth
c) It demonstrates that the hero's journey is a solitary experience
d) It highlights the idea that the hero's journey is a metaphor for personal growth