The correct answer is Sputnik-1.
Sputnik-1 was launched by the Soviet Union on 4 October 1957. It was the world's first artificial satellite to orbit the Earth, and its launch marked the start of the space age as well as the space race between the Soviet Union and the United States.
Sputnik-1 was a small metal sphere with four external antennas. It sent out simple radio signals that could be picked up by radio operators around the world, and it stayed in orbit for about three months before burning up in the atmosphere.