How can the presence of multiple DCs in branch offices affect network reliability?

The presence of multiple Domain Controllers (DCs) in branch offices can significantly enhance network reliability because it provides redundancy and ensures continuous network service during outages. If one DC fails or becomes unreachable due to a network problem, users can still authenticate and access network resources through another DC in the same branch office or elsewhere, depending on the overall network design. This redundancy minimizes downtime and ensures that critical services remain available, contributing to a more robust and reliable network structure.

The other options relate to different aspects of network operations that are either indirect effects or not directly tied to the issue of reliability. For instance, while multiple DCs can improve access speed and resource availability, the primary advantage regarding reliability is their capacity to provide uninterrupted service. Similarly, while having several DCs might complicate network topology or introduce complexities in managing access controls, these factors do not directly address how reliability is enhanced during outages.