Answer:
A. Loneliness/Alienation.
Step-by-step explanation:
John Steinbeck's novel "Of Mice and Men" revolves around the story of two men, George Milton and Lennie Small, and their experience looking for work during the Great Depression. The story also deals with themes related to the lives of ranch workers, alienation, unfulfilled dreams, discrimination, friendship, etc.
One major theme of the story is that of alienation or loneliness of the characters. Not only were George and Lennie lonely, but this loneliness also affects Curley's wife, who was the only female character in the whole story. She is surrounded by men all around, be it her husband who hardly stays with her or keeps her company, or the ranch helpers. She would venture out into the ranch to keep herself occupied, getting acquainted with the workers.
Thus, the correct answer is option A.