Resolution because they already solved the problem.
Yes, the "iron curtain" indeed refers to the imaginary boundary dividing Europe into two separate areas from the end of WWII in 1945 until the end of the Cold War in 1991. These two separate areas are Soviet Union and its satellite states from Western Europe.
A hook is the “attention catcher” of an essay or book, or any other written material. It grabs the reader’s attention and makes them want to keep reading. Therefore, it is C.
