Analogy (number progression) — (23 : 30 : 37). Choose the option that preserves a constant +7 step between consecutive terms.

Introduction / Context:
The triple 23 : 30 : 37 increases by a constant difference: +7, then +7. We must select the option with the same constant-difference pattern.

Given Data / Assumptions:

• A, B, C where B = A + d and C = B + d with the same d.
• d = 7 in the stem.

Concept / Approach:
Check each option for B - A = 7 and C - B = 7.

Step-by-Step Solution:

Verification / Alternative check:
Only the first option maintains constant +7 increments across both gaps.

Why Other Options Are Wrong:
They break the constant-difference requirement.

Common Pitfalls:
Stopping after checking the first gap; both gaps must match.

Final Answer:
(6 : 13 : 20)