Topic: Group verb,

Best Answer Explained in Below-:

The correct answer to the sentence "Many freedom fighters died. He died _____ his country." is D) for. This choice accurately conveys the idea of sacrifice and purpose. When we say someone died "for" their country, it indicates that their death was in service of a cause—specifically, the protection, freedom, or betterment of their homeland.

Using other options would change the meaning or create awkward phrasing:
- A) "by" would imply the method of death rather than the reason.
- B) "on" does not align with the intended meaning, as it suggests a time or occasion rather than motive.
- C) "of" implies a cause of death (like a disease or injury), which again does not convey the sense of sacrifice for a larger purpose.

In summary, "for" is the most appropriate preposition, as it captures the essence of altruism and commitment that aligns with the actions of freedom fighters, emphasizing their dedication to their country and the sacrifices they made.