Managing a large number of branches in an enterprise WAN environment presents several challenges. Below is an analysis of each option:

Difficulties in rectifying faults on branch networks : With numerous branches, identifying and resolving network faults becomes complex, especially when relying on manual troubleshooting.

Long time to provision new services in branches : Deploying new services across multiple branches requires significant coordination and configuration effort, leading to delays.

Poor experience with key applications : Limited bandwidth, high latency, and inefficient traffic steering can degrade the performance of critical applications like video conferencing and ERP systems.

High O&M costs : Managing distributed branch networks involves substantial operational and maintenance costs, including personnel, tools, and infrastructure expenses.

All four options accurately describe the challenges faced in enterprise WAN interconnection with large numbers of branches.