Choose the 5-letter fill that sustains the “cab / … / baca / … / cba / … / ab” rhythm without triple repeats: __cb__cab__baca__cba__ab

Introduction / Context:
The anchors “cab”, “baca”, “cba”, and the final “ab” imply a rhythm where “cab” and “cba” frame “baca”. The inserted letters must keep that rhythm while avoiding “ccc” or “bbb”.

Given Data / Assumptions:

• Template: __ cb __ cab __ baca __ cba __ ab
• Five letters inserted.
• Avoid triple repeats.

Concept / Approach:
We need a fill that starts with b/a, swings through c, then returns to b to pivot into “…cba…ab”. “bacbc” supplies a smooth b–a–c–b–c glide compatible with the anchors.

Step-by-Step Solution:

Verification / Alternative check:
Other candidates push too much c or b near “baca” or the closing “cba”.

Why Other Options Are Wrong:

• cabcb: Overlaps poorly at the very start.
• abccb: Stacks c’s near “…baca…”.
• bcaba: Mis-times a near the “…cba…” anchor.
• None of these: Not applicable.

Common Pitfalls:
Forgetting that “baca” requires balanced b and a around c.

Final Answer:
bacbc