Final answer:
Panama was part of Colombia before it became independent in 1903 with U.S. support, primarily due to the strategic interest in building the Panama Canal. The correct option is A.
Step-by-step explanation:
Panama was originally part of Colombia before it gained independence. The region, which was under Spanish control during colonial times, became independent from Spain when Colombia did in 1819. However, Panama remained a part of Colombia until 1903. Following a civil conflict in Colombia and negotiations over the construction of the Panama Canal that did not go as the U.S. had hoped, the United States supported Panama's independence movement. Strategic concerns, primarily the desire to build the Panama Canal, motivated this support.
The year 1903 marked a pivotal moment when the U.S. backed a rebellion in Panama to facilitate the canal project. This led to Panama's independence from Colombia with the help of the United States, which sent warships to prevent Colombian troops from quelling the Panamanian uprising. Subsequently, Panama became an American protectorate until 1939.
Furthermore, during the construction of the canal, the Americans, with insights from Cuban researchers, managed to control the spread of diseases such as malaria, which was rampant in the area. The canal itself, opened in 1914, was a monumental engineering achievement that significantly reduced travel time between the Atlantic and Pacific Oceans.
Hence, Option A is correct.