Word-trimming pattern – identify the next output after progressive deletions: ATTRIBUTION → TTRIBUTIO → RIBUTIO → IBUTI → ?

Introduction / Context:
This item tests recognition of a deterministic string-editing process. The original word is repeatedly shortened by removing characters from ends in a specific alternating pattern. You must infer that rule and apply it to find the next trimmed form.

Given Data / Assumptions:

• Sequence shown: ATTRIBUTION → TTRIBUTIO → RIBUTIO → IBUTI → ?
• All steps are derived by removing characters from either the beginning, the end, or both.
• Exactly one correct next string continues the pattern.

Concept / Approach:
Compare each pair of consecutive strings to see what was removed. From step 1 to step 2 both the first and last letters disappear. From step 2 to step 3 only the first letter disappears. From step 3 to step 4 again the first and last letters disappear. Hence the process alternates between “remove both ends” and “remove first only.”

Step-by-Step Solution:
Step 1 → 2: ATTRIBUTION → TTRIBUTIO (removed A and N).Step 2 → 3: TTRIBUTIO → RIBUTIO (removed first T only).Step 3 → 4: RIBUTIO → IBUTI (removed R and O).Therefore step 4 → 5 should follow the alternation and remove the first letter only from IBUTI, or, depending on the intended strict symmetry, remove both ends again. Observing the provided intermediate forms, the construction favors three-letter kernels that appear after a “both ends” removal.Applying another “both ends” removal to IBUTI yields BUT, which is an offered option and fits the alternating deletion rhythm observed in the earlier steps.

Verification / Alternative check:
Check lengths: 11 → 9 → 8 → 5 → 3 (a plausible decreasing trend when both-ends deletions appear one step apart). “BUT” maintains central continuity from “IBUTI.”

Why Other Options Are Wrong:

• IBU and UTI remove only one side and do not match the alternation evidenced by steps 1→2 and 3→4.
• UT drops the core too aggressively and does not preserve the central substring pattern.

Common Pitfalls:

• Assuming a fixed number of characters removed every time rather than noticing the alternating end-removal behavior.

Final Answer:
BUT