Correct Answer: 1, 4, 2, 8

Solution : Let's check each option –
First option: (1, 0.75, 0.50, 1.25); 1 – 0.25 = 0.75; 0.75 – 0.25 = 0.50; 1 + 0.25 = 1.25
Second option: (4, 3, 2, 5); 4 – 1 = 3; 3 – 1 = 2; 4 + 1 = 5
Third option: (1, 4, 2, 8); 1 + 3 = 4; 4 – 2 = 2; 2 + 6 = 8
Fourth option: (2, 1.5, 1, 2.5); 2 – 0.5 = 1.5; 1.5 – 0.5 = 1; 2 + 0.5 = 2.5

So, only the third option doesn't follow the same pattern as followed by the given set of numbers. Hence, the third option is correct.