The correct answer is A. Launch of Sputnik
Step-by-step explanation:
The Spatial Race was a competition for space exploration during the Cold War (1946-1991) and between the U.S. and the Soviet Union. Because of this, during this historical period many events related to space exploration took place, the first event was the launch of Sputnik I by the Soviet Union that took place in 1957 and was the first artificial satellite of Earth, this event was followed by other that implied important advancements in the space area including the beginning of the Project Mercury by the Nasa in 1958 which aimed at sending man to the Earth orbit, U.S. land on the moon in 1969 and the first station called Salyut 1by the Soviet Union in 1971. Considering this, the first event from options provided and in the spatial race was the Launch of Sputnik that occurred in 1957.