YANG (Yet Another Next Generation) is a data modeling language defined by the IETF in RFC 7950. It is an open standard designed to model the configuration and state data of network devices. Its purpose is to provide a standardized, human-readable, and machine-processable way to define management data, superseding older methods like SNMP with MIBs (Management Information Bases). YANG is fundamentally independent of MIBs and does not require them for its operation; in fact, it is often positioned as a modern replacement for the SNMP/MIB framework.

A. YANG models are hierarchically structured using nodes like 'containers' to group related data and 'leaves' to define individual data items, making this a core concept.

B. NETCONF and RESTCONF are standard network management protocols specifically designed to use YANG models for transporting and manipulating configuration and state data on network devices.

D. A key feature of YANG is its explicit ability to distinguish between configuration data (which can be written to the device) and state data (read-only operational information).

1. IETF RFC 7950: The YANG 1.1 Data Modeling Language.

For C (Correct Answer): Section 1, "Introduction," contrasts YANG with SMIv2 (used for SNMP MIBs), highlighting YANG's advantages and establishing it as a distinct and separate technology, not a dependent one. It makes no mention of requiring MIBs.

For A: Sections 7.5 ("The container Statement") and 7.6 ("The leaf Statement") define these as fundamental constructs for building the data tree.

For D: Section 7.2.1, "The config Statement," explicitly defines the mechanism for separating configuration (config true) from state data (config false).

2. IETF RFC 6241: Network Configuration Protocol (NETCONF).

For B: Section 1, "Introduction," states, "The YANG data modeling language (RFC 7950) is used to model the configuration and state data of NETCONF clients and servers." This directly links YANG models to their transport via NETCONF.

3. IETF RFC 8040: RESTCONF Protocol.

For B: Section 1.1, "Terminology," clearly states that RESTCONF is a protocol for accessing data defined in YANG.

4. Nokia SR OS System Management Guide (e.g., Release 22.10.R1).

For C: The guide contains separate, distinct chapters for SNMP management (using MIBs) and Model-Driven Management (using YANG/NETCONF/gNMI). This architectural separation in the official vendor documentation demonstrates that YANG does not require MIBs. (See chapters on "SNMP" vs. "Model-driven management").