Answer:
It's B: He would grow used to the light of reality in stages.
Step-by-step explanation:
As stated in the article, when the prisoners leaves the cave, at first, he will suffer sharp pains, become distressed by the glare, and will be unable to see the truth and reality. But as they stay in the light, they will realize that everything they saw before was an illusion and will get a clearer vision. At that point, they can see the truth about life and what it's about.