Which answer matches this clue: Elio Petri's 1971 Palme d'Or-winning film about a factory worker's radicalisation?

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

The Working Class Goes to Heaven, starring Gian Maria Volonté, is a fierce political satire of both capitalist exploitation and trade-union bureaucracy.