If an online ride-hailing platform plans to adjust its pricing mechanisms or rate structures, what is the mandatory advance public disclosure requirement?

1. The platform must announce the changes 1 hour prior to implementation on social media
2. The platform must publicly announce the proposed pricing adjustments at least 7 days in advance (提前7日向社会公布)
3. The platform is not required to give advance notice if competitors have already adjusted prices
4. The platform must notify each registered passenger via postal registered letter 30 days in advance