Rule reminder
Concessive conjunctions (sebbene, benché, nonostante che, quantunque, per quanto) ALWAYS require the subjunctive (congiuntivo), never the indicative or conditional. Common errors: using indicative after sebbene/benché, using the wrong tense of subjunctive, or confusing the congiuntivo imperfetto and trapassato. 'Anche se' is the only concessive connective that can take the indicative (for real concessions).
Which sentence contains an ERROR?