Answer:
A). To create a vivid description of Walden's former beauty.
Step-by-step explanation:
In 'Earth's Eye', Thoreau employs the quotation from 1821 to 'offer a more vivid and lucid description of Walden's former beauty' which allowed him to be more soulful, liberated, and connected to nature and explore the ideas of self-reliance, simplicity, and association to nature. His descriptions of 'a lake is the landscape's most expressive feature', 'fluviatile trees, overhanging brows', 'earth's eye' through 'beholder can measure the depth of his nature', etc. portray this evocative and striking beauty of Walden. Thus, option A is the correct answer.