When should traffic shaping be implemented on Frame Relay PVCs？（）
- AWhen you want to drop excess traffic above the CIR
- BWhen there is a speed mismatch between the central site and the remote site
- CWhen using Frame Relay SVCs
- DWhen over-subscribing the central site link
- EWhen LLQ is implemented on the Frame Relay PVC
- FWhen Multilink PPP LFI is implemented on the Frame Relay PVC