Comprehensive and Detailed In-Depth Explanation:

According to ISO 9000:2015, which provides definitions for terms used in ISO 9001:2015, a management system is defined as a set of interrelated or interacting elements of an organization to establish policies, objectives, and processes to achieve those objectives.

A Quality Management System (QMS) is a type of management system that ensures organizations meet customer and regulatory requirements while improving performance.

Clause 3.5.3 of ISO 9000:2015 clearly defines "management system" and aligns with this question. The other options do not fit the definition:

Standard refers to an established norm or requirement.

Organization scope defines the boundaries of a QMS but is not a system itself.

Quality manual is a document (optional under ISO 9001:2015) that describes a QMS but is not the system itself.