Answer:
A. Its location between Germany and Russia made it vulnerable to invasion
Step-by-step explanation:
Since Poland is very close to Germany and in the past Poland used to belong to the reich, one of the first moves taken by the German army was to invade poland and take it under their control, it was too sudden and too fast for other nations to do anything about it, and it was strategically well done because then poland would create a land shield against the soviet army, they tried to do the same with France, and to a certain degree they managed to do so.