Based on the sentence provided, the answer is d) An unusual style.
Based on the sentence, a quirky style would be described as (d) an unusual style. This can be inferred from the fact that Betty's sense of humor is described as "off-beat," which means it is unconventional or different from what is expected. Additionally, the mention of her pink hair, 80s costume jewelry, and oversized men's suits further suggests that her style is not typical or mainstream. Therefore, option (d), an unusual style, is the correct answer.
