Which of the following is a key responsibility of a network administrator?

Managing and maintaining computer networks is a fundamental responsibility of a network administrator. This role involves ensuring that the network infrastructure operates efficiently and reliably. Network administrators configure, deploy, and monitor network devices like routers, switches, and firewalls to ensure connectivity and security. They are also responsible for troubleshooting issues that arise within the network, optimizing performance, and applying updates or patches to network software and hardware as needed.

In this role, the network administrator plays a crucial part in maintaining the connectivity between devices and managing data traffic across the network, which ultimately supports the organization's operations. This responsibility encompasses various tasks, such as managing user access, implementing security protocols, and ensuring backup and recovery measures are in place, making it a central focus of network administration.

The other options, while important in their respective fields, do not align with the primary duties of a network administrator. Developing software applications and designing user interfaces fall under software development roles, whereas data analysis and reporting pertain more to data analytics or business intelligence roles. Thus, the key responsibility remains focused on network management and maintenance.