Correct Answer: 125 : 218

Solution : Let's check the options –
First option: 1 – 8→1 ³ = 1; 2 ³ = 8
Second option: 27 – 64→ 3 ³ = 27; 4 ³ = 64
Third option: 125 – 218→ 5 ³ = 125; 6 ³ = 216 ≠ 218
Fourth option: 343 – 512→ 7 ³ = 343; 8 ³ = 512

So, the third option is different from the other three options as the second number is not a perfect cube of consecutive natural numbers. Hence, the third option is correct.