The Apollo Program
The correct answer is A. Apollo program.

The Apollo Program was a series of space missions conducted by NASA (National Aeronautics and Space Administration) in the 1960s and 1970s. Its primary goal was to send humans to the moon and bring them back safely to Earth. The program consisted of several missions, with the first manned mission being Apollo 7 and the final mission being Apollo 17. However, the mission that brought the first humans to the moon was Apollo 11.

Apollo 11
Apollo 11 was the fifth manned mission in the Apollo Program. It was launched on July 16, 1969, from the Kennedy Space Center in Florida, USA. The crew of Apollo 11 consisted of three astronauts: Neil Armstrong, Edwin "Buzz" Aldrin, and Michael Collins. The mission lasted for a total of eight days.

Landing on the Moon
On July 20, 1969, the lunar module named "Eagle" separated from the command module and descended towards the moon's surface. Neil Armstrong and Buzz Aldrin were inside the lunar module. As the lunar module approached the moon's surface, Armstrong reported, "The Eagle has landed." This historic landing took place in the Sea of Tranquility region of the moon.

First Steps on the Moon
Several hours later, on July 21, 1969, Neil Armstrong became the first human to set foot on the moon. As he descended the ladder of the lunar module, Armstrong famously said, "That's one small step for man, one giant leap for mankind." Buzz Aldrin joined him shortly after, and together they conducted experiments, collected samples, and planted the American flag on the lunar surface.

Return to Earth
After spending a total of about two and a half hours on the moon's surface, Armstrong and Aldrin returned to the lunar module. They lifted off from the moon on July 21 and docked with the command module, where Michael Collins was waiting for them. The crew then began their journey back to Earth and splashed down in the Pacific Ocean on July 24, 1969.

Conclusion
The Apollo 11 mission was a monumental achievement for NASA and the United States. It marked the first time humans set foot on another celestial body, and it remains one of the most significant milestones in human space exploration. The success of Apollo 11 paved the way for further lunar missions and expanded our understanding of the moon and the universe.

Apollo progrrame