(3 - 12) , (4 - 20) , (6 - 42) , (7 63)
Option:
Justification: In all other pairs, (1st number) × (1st number + 1) = 2nd number.

(3 - 12) , (4 - 20) , (6 - 42) , (7 63)
Justification: In all other pairs, (1st number) × (1st number + 1) = 2nd number.