Complete the historian's dramatic podcast script by selecting the adverb that best expresses the speaker's stance on the claim.

The mayor's decision to build the town's new flood defenses out of recycled cardboard was, _____, the most spectacularly terrible municipal choice of the decade.

The correct answer is arguably.

"Arguably" is an epistemic sentence adverb. It modifies the entire claim, showing the speaker's stance that while stating it was the "most spectacularly terrible choice" is a strong opinion, it can absolutely be supported by good evidence.

"Inadvertently" means accidentally, "mutually" requires a shared action between parties, and "marginally" means only slightly—none of which fit the historian's bold declaration.