Answer:
C. Actions that are brave.
Explanation:
With the use of the word "American Heroes", it can only be inferred that the passage or article or literary work deals with the extreme sacrifice of the brave souls in keeping America safe. They had brought or given a huge 'gift' that is incomparable to anything else. They gave up their lives and careers and other more precious things in favor for the betterment of their fellow people and future generations' lives.
The "contributions" in the given sentence/ speech as used in "American Heroes" will/ can only mean the brave actions of the people who were fighting for the American people.
