The suggested answer is A, C, F.
A Tier-0 Gateway in a multi-tenant service provider environment performs several critical functions. Firstly, it acts as a default gateway for tenant workloads, handling their initial routing needs. It also interconnects the Tier-1 gateways of multiple tenants, facilitating communication between different tenants' networks. Lastly, it enables north-south connectivity to tenant workloads, managing traffic that flows in and out of the data center or cloud environment, ensuring proper ingress and egress routing.