In the series _b_a_ba_b_abab_aab; fill in the six blanks ( _ ) using one of the following given four choices such that the series follows a specific order.
Answer & explanation
Answer: (d) ababab
Filling the blanks with a, b, a, b, a, b turns the series into abbaab abbaab abbaab — one six-letter block repeated three times. None of the other choices produces a repeating block.
- The series has 18 places, so look for a repeating block of 6 (or 3, 9).
- Fill the blanks with a, b, a, b, a, b: abbaababbaababbaab.
- This splits as abbaab | abbaab | abbaab — the same block three times.
- Check: bababa gives bbaabbaabbababaaab, which has no repeating block.
Remember · For letter-series gaps, count the length and test whether the filled series splits into equal repeating blocks.
Question and answer: UPSC's official GS Paper II (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·