Which law, passed in 1976, established the nine-year compulsory education system and replaced Katharevousa with Demotic as the language of instruction?

• A Law 1566
• B Law 2525
• C Law 309 ✓
• D Law 4186

Law 309/1976 reformed Greek education by extending compulsory schooling to nine years, adopting Demotic Greek as the official language of instruction, and restructuring secondary education into gymnasium and lyceum.