What describes the use of best-effort service with overprovisioning?

A.
ensuring quality of service by providing more than the aggregate bandwidth required

B.
ensuring constant availability by provisioning multiple paths through the network

C.
ensuring quality of service by deploying sophisticated prioritization and congestion management mechanisms

D.
ensuring quality of service by being able to load balance across links in times of congestion

E.
ensuring availability and quality of service by always provisioning key services across at least two service provider networks