A. of
B. about
C. on
D. in
🧠 Explanation:
In the phrase “I am envious __ them,” the blank is filled by “of,” as in “envious of them.” This preposition correctly conveys jealousy or desire for what others possess. Commonly used in English, “envious of” is grammatically precise, as in “She is envious of their success.” Understanding this usage clarifies emotional expressions in language, enhancing communication in both casual and formal contexts. Prepositions like “of” are vital for accurate sentence construction, ensuring clarity when describing feelings or comparisons in everyday or literary discussions.