The question is kind of tricky. D-Day was the code word for the Allied invasion of France, so D is definitely a possible answer. But the PURPOSE of that invasion was in part to defend Britain, which at the time was being threatened by Nazi air attacks and by a possible Nazi invasion. So A is possible as well.
The overthrow of Mussolini was certainly a factor in the Allied strategy, but the invasion of Italy, not France, was how that task was accomplished. So C is out.
There's competing evidence over how much the Allies knew about Auschwitz by the time of D-Day. Either way, the immediate purpose of D-Day was not to free the Jews from Auschwitz, though that was an ultimate result of D-Day. So B is out.
Since the question is asking the PURPOSE of D-Day, I think A is the best answer. D is more of a description of what D-Day WAS rather than an explanation of its PURPOSE.
Answer:The objective of the Congress was to provide a long-term peace plan for Europe by settling critical issues arising from the French Revolutionary Wars and the Napoleonic Wars. The goal was not simply to restore old boundaries but to resize the main powers so they could balance each other and remain at peace.
