Instruction: Provide an example of how you would use Excel's 'Data Validation' feature to ensure data integrity in a spreadsheet tracking monthly expenses across different departments.
Context: This question is designed to assess the candidate's understanding and application of Excel's 'Data Validation' feature to prevent data entry errors. Candidates should explain how to set up data validation rules that restrict input to certain types such as numeric ranges or specific text, thereby maintaining accurate and reliable data in business-critical spreadsheets.