Which of the following tools will scan a network for hosts and provide information on the installed operating system?

DOCSIS (Data Over Cable Service Interface Specification) is a standard for providing internet access over cable TV infrastructure - it is not a scanning or diagnostic tool.

Nmap uses techniques such as TCP/IP stack fingerprinting (the -O flag) to identify the operating system of remote hosts, and it can also enumerate open ports, services, and connected devices across a network, making it the correct tool for both host discovery and OS detection.

IMAP (Internet Message Access Protocol) is an email retrieval protocol used to access mailboxes on a mail server - it has no network scanning functionality.

BERT (Bit Error Rate Test) measures the quality of a transmission line by counting bit errors - it does not scan for hosts or identify operating systems.