Yuri Gagarin, a Soviet cosmonaut, became the first human to orbit the Earth on April 12, 1961, marking a significant milestone in space exploration.
Step 1: Significance of the mission
Gagarin's flight demonstrated the possibility of human space travel and intensified the space race during the Cold War.
Step 2: Other astronauts
- John Glenn was the first American to orbit Earth.
- Valentina Tereshkova was the first woman in space.
- Neil Armstrong was the first human to walk on the Moon.
Therefore, option (A) is correct.