Final answer:
Roman soldiers who served for 20 to 25 years were rewarded with a plot of land and a lump sum of 2000 denarii.
Step-by-step explanation:
In ancient Rome, soldiers who had served for a certain period of time could look forward to an honorable discharge. The correct answer is option C: 20, 25, 2000, a plot of land. After serving for 20 to 25 years, a Roman soldier would receive a lump sum of 2000 denarii and a plot of land as a reward for their service. This was a significant incentive for soldiers to serve in the Roman army, as it offered the potential for wealth and a secure future.