You are absolutely correct! Out of the options provided, decision modelling (D) is the most suitable technique for modeling the rationale of a change.

Here’s why the other options are less relevant:

• Roles and Permissions Matrix: This defines access controls for users within a system, not the reasoning behind a change.
• Organizational Modelling: This focuses on structuring and visualizing an organization’s components, not the justification for change.
• Business Capability Analysis: This identifies and assesses an organization’s capabilities, not necessarily the reasons for modifying them.

Decision modelling, on the other hand, explicitly focuses on capturing the logic and reasoning behind a decision or change. It allows you to represent the factors involved, the potential consequences, and the criteria used to arrive at the chosen course of action. This makes it a valuable tool for understanding and communicating the rationale behind changes.