The inspection of a RACI (Responsible, Accountable, Consulted, Informed) matrix for best practice content is a test of a control's design effectiveness. A RACI matrix is a control mechanism that clarifies roles and responsibilities to ensure processes operate as intended and objectives are met. By evaluating its content against established best practices, the assurance provider is assessing whether the control is properly designed to prevent or detect issues related to accountability and responsibility. This is a core function of a control test, which focuses on the control's design and operating effectiveness, rather than verifying the substance of individual transactions or data points.

B. Substantive test: This is incorrect because a substantive test is designed to detect material misstatements in data, such as financial account balances or transactions, not to evaluate the control itself.

1. OCEG GRC Capability Model 3.5 (The "Red Book"):

Section 4.3, Test Controls: "Testing is the process of verifying that controls are designed appropriately and operating effectively." The scenario describes an inspection to verify the appropriate design of the RACI matrix (a control), which aligns perfectly with this definition of a control test.

Glossary, Definition of Control: A control is defined as "An activity or set of activities designed to ensure that a desired outcome is achieved, an undesired outcome is prevented, or progress toward objectives is made." A RACI matrix serves this purpose by preventing confusion over roles.

2. University of Illinois at Urbana-Champaign, Courseware (ACCY 405 - Assurance and Attestation):

Lecture Notes on Audit Evidence and Procedures: "Tests of controls are audit procedures to test the effectiveness of controls in support of a reduced assessed control risk... Substantive tests of transactions are to test for dollar misstatements... in the financial statements." The inspection of a RACI matrix is a test of the control's effectiveness, not a test for dollar misstatements. This distinction is a fundamental principle in auditing and assurance education.