The phrase "I am glad to see veil after veil lift gradually" primarily describes Keller's happiness in discovering things that are hidden in the lines and words of Shakespeare. This metaphor conveys her sense of excitement and joy as she uncovers deeper meanings and insights in the text, suggesting a journey of enlightenment and intellectual growth. Each "veil" that is lifted represents an increased understanding, indicating that her study of Shakespeare is enriching her appreciation of literature. Therefore, the most fitting response is:
It describes Keller's happiness in discovering things that are hidden in the lines and words of Shakespeare.