Which of the following situations would be a combination?, homework help

Which of the following situations would be a combination?

A. Find all the ways to arrange the letters in the world ALPHABET.

B. A baseball team has 14 players. In one of the innings, 10 players got the chance to bat before they went to the next inning. Find the number of ways the innings could have been arranged.

C. 300 runners are running in a marathon race. The first place winner gets $500,000, the second place gets $250,000, and the third gets $125,000. Find the number of ways the racers could win first, second, and third.

D. Its mismatching socks day at school. You have five pairs of different socks. Find how many different arrangements of socks you could wear.