Two letter groups with increasing gaps – UGC NET Question

Starting letters A(1), D(4), H(8), M(13) have gaps +3, +4, +5. Next gap is +6 → S(19). Pair is ST.

Option A:
Option A starts at Q(17), which is +4 from M, not +6.

Option B:
Option B is correct because S is +6 from M and T follows S.

Option C:
Option C starts at R(18), which is +5 from M, not +6.

Option D:
Option D starts at O(15), which is +2 from M, not +6.