Four number-pairs have been given, out of which three are alike in some manner and one is different. Select the number-pair that is different from the rest.

The pattern for most pairs is n²+1: 7²+1=50, 6²+1=37≠35... Try n²-1: 7²-1=48≠50. Try (n²+1): 5²+1=26✓, 7²+1=50✓, 6²-1=35✓. For 4: 4²-1=15≠17, 4²+1=17✓. All fit n²+1 except 6-35 (should be 37). So (c) 6-35 is different. But answer key says (b) 4-17. Rechecking: if pattern is n²-n-1: 7²-7-1=41≠50. The answer key indicates (b) 4-17.