OVAL (Open Vulnerability and Assessment Language) is an international, information security standards language designed to standardize the transfer of security vulnerability and configuration information across different tools and services. Its primary purpose is to enable organizations to assess and report on the security state of computer systems consistently.
OVAL is an XML-based schema designed to describe the security state of a system.
An example of OVAL schema:

The Definitions component is a critical part of OVAL's architecture. It provides a structured way to describe specific conditions or criteria that can be used to evaluate the security state of a system.
For example, a definition might specify criteria like:
β Checking if a specific software version is installed
β Verifying a particular system configuration setting
β Examining patch levels of operating systems or applications
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B) OVAL exclusively focuses on defining network protocols for vulnerability scanning without addressing system configurations. OVAL is much broader than just network protocols. It's designed to assess a wide range of system states, including file systems, registry settings, installed software, and other local system configurations, in addition to network-related items.
C) OVAL does not support the integration of custom extensions or user-defined elements within its framework. OVAL is designed to be extensible. While it has a standard set of definitions, it allows for extensions to address specific needs or proprietary software.
D) OVAL is primarily designed for real-time intrusion prevention and does not facilitate vulnerability assessment. OVAL is primarily for vulnerability assessment. It helps identify vulnerabilities before they are exploited. While the information gathered by OVAL could inform intrusion prevention systems, that's not its primary purpose. Its main function is to provide a standardized way to describe and check for vulnerabilities.