The correct answer to the question is:
C. appeared that the United States had failed to keep up in scientific achievement
Explanation:
1. The launch of Sputnik in 1957 by the Soviet Union was the first artificial Earth satellite in history.
2. This event shocked and embarrassed the United States because it showcased the Soviet Union's advancement in space technology and scientific achievement.
3. The successful launch of Sputnik gave the impression that the United States had fallen behind in the space race and scientific prowess, leading to concerns about national security and technological superiority.
4. It prompted the U.S. to intensify its efforts in space exploration, resulting in the establishment of NASA and the eventual moon landing in 1969 as part of the Apollo program.
