Out of the given options, 2 – 12 is odd one because in all other options 2nd term is square of the 1st term i.e. 12 – 144 → 12 × 12 = 144 8 – 64 → 8 × 8 = 64 18 – 324 → 18 × 18 = 324 But in 2 – 12 → 2 × 2 = 4 which is not equal to 12. Thus, 2 – 12 is odd one.