The requirement is to restrict data access so that users can only view data corresponding to their specific department. This is the primary use case for Row-Level Security (RLS) in Power BI. RLS is implemented by creating roles within the Power BI model. For each role, a DAX filter expression is defined on a table (in this case, the Departments table). When a user assigned to a specific role accesses the report in the Power BI service, this DAX filter is automatically applied, restricting the rows of data they can see throughout the entire model. This method enforces security at the data model level.

B. A parameter is a user-controlled input for interactive analysis, not a security feature. A user could easily change the parameter value to view data from other departments.

C. The CURRENTGROUP DAX function is used within grouping functions like SUMMARIZECOLUMNS to perform calculations on grouped data; it is not related to user-based security.

D. A slicer is a visual filter on the report canvas that users can freely interact with. It does not enforce security, as a user could modify or remove the slicer.

1. Microsoft Learn. (2024). Restrict data access with row-level security (RLS) for Power BI. Microsoft Power BI Documentation. Retrieved from https://learn.microsoft.com/en-us/power-bi/enterprise/service-admin-rls.

Reference Details: The section "Define roles and rules in Power BI Desktop" explicitly states

"You can define roles and rules within Power BI Desktop. When you publish to Power BI

it also publishes the role definitions... To define security roles

follow these steps. 1. Import data into your Power BI Desktop report

or configure a DirectQuery connection. ... 2. From the Modeling tab

select Manage Roles." This directly supports the process described in option A.

2. Microsoft Learn. (2024). Implement row-level security. PL-300: Design and build a data model in Power BI learning path. Retrieved from https://learn.microsoft.com/en-us/training/modules/design-build-tabular-model-power-bi/7-implement-row-level-security.

Reference Details: This official PL-300 courseware notes

"Row-level security (RLS) is a Power BI feature that can be used to restrict data access for given users. Filters restrict data access at the row level

and you can define filters within roles... You will implement RLS by creating one or more roles. A role has a unique name in the model

and it will typically include one or more rules."

3. Microsoft Learn. (2024). Row-level security (RLS) guidance in Power BI Desktop. Power BI Guidance Documentation. Retrieved from https://learn.microsoft.com/en-us/power-bi/guidance/rls-guidance.

Reference Details: The section "Implement RLS" details the process: "In Power BI Desktop

you can create a role by navigating to the Modeling ribbon and selecting Manage roles. In the Manage roles window

you can create

modify

or delete roles... You add a rule to a table by using a DAX expression that must return a TRUE or FALSE value." This confirms that creating roles and defining rules is the correct procedure.