What is the statutory time frame within which a bus carrier must process and definitively answer a passenger complaint under Article 27 of Regulation (EU) No 181/2011?

1. Within 1 month the carrier must give notice that the complaint has been substantiated, rejected, or is still being considered; the final reasoned response must be given within 3 months of receipt
2. Within 24 hours the carrier must pay EUR 1,000 cash
3. The carrier has up to 2 years with no intermediate notification required
4. Carriers are not legally required to reply to passenger complaints