To create a drop-down list, select cell where you want it to be (in this case, cell I2), and in the Data tab on the ribbon, click "Data Validation" in the drop-down option with the same name.

To create a drop-down list in Excel, you will use the Data Validation feature. This feature enables you to set specific criteria for the data that can be entered into a cell.

Learn to create efficient, interconnected Excel drop-down lists using range functions and data validation techniques. Multi-level drop-down ...