What are three functions of a Tier-0 Gateway in a multi-tenant service provider environment?

What are three functions of a Tier-0 Gateway in a multi-tenant service provider environment? (Choose three.)
A. acts as a default gateway for the tenant workloads
B. enables east-west connectivity to the tenant workloads
C. interconnects the Tier-1 gateways of multiple tenants
D. provides isolation between the tenants
E. provides first-hop routing for the tenant workloads
F. enables north-south connectivity to the tenant workloads