Couple or Pair пожалуйста решите умоляю

0 – couple, 1 – pair, 2 – couple, 3 – couple, 4 – pair, 5 – pair, couple, 6 – couple, 7 – couple, 8 – pair,  9 – pair, 10 – couple, 11 – couples, 12 – pair, 13 – pair, 14 – couple, 15 – couple, 16 – pair, 17 – couple, 18 – couple, 19 -  pair