Which conclusion about the pole vaulters scores is true?

a) more than half of the pole vaulters scored higher on the second vault than on the first vault

b) the lower a pole vaulters first vault score, the higher the pole vaulters second vault score

c) the higher a pole vaulters first vault score, the higher the pole vaulters second vault score

d) more than half of the pole vaulters scored higher on the first vault than on the second vault