Which answer matches this clue: Elio Petri's 1970 thriller about a police inspector who murders his mistress to test whether the system can touch him?

• A The Working Class Goes to Heaven
• B Property Is No Longer a Theft
• C Todo modo
• D Investigation of a Citizen Above Suspicion ✓

Investigation of a Citizen Above Suspicion won the Oscar for Best Foreign Language Film; it is a corrosive satire of institutional corruption.