Though the mayor's speech was widely lauded for its rhetorical flourish, critics argued that it ultimately proved ______, offering grand pronouncements without any ______ plans for implementation.

✓ Correct Answer: Option C

The speech was 'lauded for its rhetorical flourish' but critics found it '______,' offering 'grand pronouncements without any ______ plans.' 'Vapid' (lacking spirit, liveliness, or substance) fits the first blank, and 'concrete' (specific, definite) fits the second, describing a lack of tangible plans.