Two letter blocks with growing gaps – UGC NET Question

Each term is a pair of consecutive letters. The starting letters A(1), D(4), G(7), J(10) increase by +3 each time. Next start is M(13), so the pair is MN.

Option A:
Option A starts at K(11), which is +1 from J, not +3.

Option B:
Option B is correct because M is +3 from J and N follows M.

Option C:
Option C starts at L(12), which is +2 from J, not +3.

Option D:
Option D starts at N(14), which is +4 from J, not +3.