Determine if the situation is a permutation or combination and then compute the number of arrangements. a. The number of ways 6 friends can be seated in a row at a movie theater b. The number of ways a jury of 12 can be selected from a pool of 20 c. The number of 5-digit pin codes if no digit can be repeated d. The number of ways you can choose 4 books from a selection of 8 to bring on vacation