Answer:
O A. The theme is mythology, and the historical context is the preoccupation with origins and "roots."
Step-by-step explanation:
As given in the passage, the critic states that the main purpose of J. R. R. Tolkien in creating the world of "The Lord of the Rings" was to provide a mythological world for the English-speaking people. While there are numerous Greek and Norse myths since ancient times, there seems to be none for the English-speaking people.
And in doing so, Tolkien has managed to provide a whole myth for them through the world of "The Lord of the Rings". This identifies with the theme of mythology that the people want for themselves according to the myths of the ancient Greeks and Norse. At the same time, the historical context seems to be the society's preoccupation with the idea of the origins and "roots" of the people and the need to align themselves with such myths that they can call or accept as theirs.
Thus, the correct answer is option A.