D)It helps reveal that, despite his adventuring, there is still a part of Bilbo that enjoys what is familiar and comfortable.
Explanation:
In the Hobbit Saga, Bilbo Baggins makes a long trip all over the Middle Earth, encountering many characters and living many adventures. However, he returns to his home in the Shire, Bag-End, and the setting at the end of the books tells us that Bilbo Baggins still feels at home in that place.
