(单选题)An instructor has obtained the set of N=20 exam scores shown here. To help organize these scores, we will place them in a frequency distribution table. The scores are: 82, 75, 88, 93, 53, 84, 87, 58, 72, 94, 69, 84, 61, 91, 64, 87, 84, 70, 76, 89.Which is the lowest score?