I believe it was a trial upon Ethel and Julius Rosenberg. The couple were accused of selling nuclear secrets to the Russians, but treason could not be held since the U.S was not at war with the Soviet Union.
The oil fields would enable Germany to fuel their air forces, making them harder to defeat.
The PPC (or PPF, same thing) shows economic growth because it outlines exactly what the economy can produce at that moment. When it shifts outward in any way (be it towards consumer and capital goods, or X and Y), that MUST be because of economic growth.
Answer: C. African Americans in the North
Explanation: This answer is from my edge notes.