Using probability to make fair decisions

Problem

In World War II, during the summer of 1944, the Russians were driving back the Germans. Stalin wanted to launch a fierce attack at one of three spots in western Russia: the north, the south, or the center. He also wanted to be completely unpredictable in his decision.
Which of the following would have been fair methods for deciding where to attack?
(Consider a system to be fair when the probabilities of each event are equal.)
Select all that apply.
Select all that apply.