✅ 1. Conclusive

Explanation:

• Incontrovertible means not open to doubt or question; undeniable.

• Conclusive means serving to prove a case; decisive or convincing, which fits the meaning well.

Why not the others?

• Disputable – ❌ Opposite in meaning; it means something open to doubt or challenge.

• Inconvenient – ❌ Has nothing to do with truth or evidence; it means causing trouble or discomfort.

• Indecisive – ❌ Means not settling an issue or lacking a clear result, again the opposite of “incontrovertible.”

Final Sentence with the correct word:

The weapon inspector's report was not expected to provide conclusive evidence of weapons of mass destruction.