Normally the report prepared for a department is a/an

The correct answer would be Internal Report.

Explanation:

Normally the report prepared for a department is an Internal Report. When there is some task related to a specific department and needs to be addressed to the upper level of the same department, then usually an internal report is generated. This report is used for the internal work/purpose of the department.

If we talk about the whole organization, and then ask about the report which is for the use of the organization only, then that would be a balance sheet. Because balance sheet is the statement or report which gives an insight into the assets, liabilities and equity of the organization at the moment.

But in this question it is asked that normally the report prepared for a department is called what. Then the appropriate answer would be an Internal Report.