The correct answer is A.
Wernher von Braun (1912 – 1977) was a German space architect who, after having worked for Nazi Germany during WWII, was transfered together with his team to the US, where they were assimilated into the NASA. At NASA, he was able to participate, even adopting leading roles, in important missions such as the launch of the first space satellite performed by the US (the Explorer 1) or the landing of the Apollo spacecraft in the Moon.
The abovementioned NASA missions, were part of the so-called space race that ocurred during the Cold War era, in which the US and URSS competed for being the worlwide leader in space-related achievements (and in many other fields), as a manner of showing their power.