Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the following quest...

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the following questions from 21 to 30.

The space race began on October 4, 1957, when the Soviet Union launched Sputnik, the first artificial satellite, shifting Cold War tensions into space. The Soviets’ use of the R7 rocket, originally designed as an intercontinental ballistic missile (ICBM), alarmed the U.S., which feared potential nuclear threats. This technological rivalry originated in World War II when Germany’s V2 rocket program influenced both nations’ space ambitions. The U.S. soon joined the competition, attempting to launch its own satellite.

On January 31, 1958, the U.S. successfully launched Explorer I, confirming the existence of the Van Allen radiation belts. This mission was led by Wernher von Braun, a former Nazi scientist brought to the U.S. through Operation Paperclip. Both the U.S. and U.S.S.R. had recruited German rocket experts after World War II, prioritizing their technical skills despite ethical concerns. The U.S. formed NASA in 1958, consolidating its space programs while the Soviet Union continued its successes under Sergei Korolev.

[I] The Soviet Union advanced in the space race by launching Sputnik II, carrying Laika, the first living creature in space. [II] Then, on April 12, 1961, Yuri Gagarin became the first human to orbit Earth, marking another Soviet victory. [III] Determined to regain leadership, U.S. President John F. Kennedy set a bold goal to land an astronaut on the Moon before the decade ended. [IV] This ambition led to Project Gemini and later Project Apollo.

After years of preparation, Apollo 11 successfully landed on the Moon in 1969, with Neil Armstrong becoming the first human to walk on its surface. This achievement marked a turning point in the space race, while the Soviet Union failed to match the U.S. success.

The Moon landing solidified U.S. dominance in space exploration, effectively ending the space race. Despite the Cold War competition fading, both nations continued their space programs, eventually collaborating on projects like the International Space Station. Today, space exploration remains a global pursuit, with multiple countries contributing to scientific advancements beyond Earth.

(Adapted from https://education.nationalgeographic.org)

Question 21. The word “alarmed” in paragraph 1 could best be replaced by:

A. unaffected                B. concerned                        C. ignored                        D. encouraged