In Windows, what does the User Account Control (UAC) feature do?

User Account Control (UAC) is a crucial feature in Windows designed to enhance security by preventing unauthorized changes to the operating system. When a program attempts to make changes that require administrative privileges, UAC prompts the user for permission. This safeguard helps to ensure that only trusted software can make significant alterations to system settings, thereby reducing the risk of malware or unauthorized applications making harmful changes without the user's knowledge.

This feature operates by asking users to confirm their intent or to enter an administrator password, depending on their account type. Consequently, UAC not only informs users when changes are being made but also provides an additional layer of security by mitigating the risks associated with unintentional changes to important settings or installations of potentially harmful software.

In contrast, the other options describe functionalities that are not related to UAC: enabling multiple users to log in concurrently refers to user session capabilities, managing network connections is not a function of UAC but rather part of network configuration settings, and improving operating system performance is unrelated to user permission prompts and system changes. Hence, the focus of UAC on user permissions and security makes it distinct and vital for protecting the integrity of the Windows operating system.