Answer:
a. The building of the Panama Canal
Step-by-step explanation:
The building of the Panama Canal was and still remains the greatest technological endeavor of the United States for it cost up to $500,000,000 before it reached its completion. The Canal was to make plying between the Pacific and Atlantic Oceans easier, less expensive, and faster for commercial and military shipping. Several other nations like the United Kingdom and France had attempted to undertake this project but they all failed.
The United States under the government of Theodore Roosevelt undertook and completed this project from 1904 to 1914. It was a great feat that announced the United States' power to the world.