Answer:
B
Explanation:
There are 4 countries. If a country places first, it cannot place 2nd or 3rd or fourth. That leaves 3 that can. So this uses the counting principle
4 countries could be first
3 countries could be second
2 countries could be 3rd
1 country can be last.
4*3 * 2 * 1 = 24 different ways.