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.)

a) Stalin asks one of his officers to choose the place of attack.

b) Stalin rolls three 6-sided dice. If all 3 numbers are different, he attacks in the north. If all 3 numbers are the same, he attacks in the south. If 2 numbers are the same and the other is different, he attacks in the center.

c) Stalin flips 2 coins. If the first coin is heads, he attacks in the north and ignores the second coin; if it is tails he rules out attacking the north and moves on to the second coin. If he gets to the second coin and it is heads, he attacks in the center; if it is tails he attacks in the south.

d) Stalin writes down the numbers 1, 2, or 3 on pieces of paper. He asks his leading officer to choose one of the pieces from a hat. If the officer chooses 1, they attack in the north. If the officer chooses 2, they attack in the center. If the officer chooses 3, they attack in the south.