This macro will run MacroA when the first item is selected, MacroB when the second item is selected, and MacroC when the third item is selected. The only code changes you would need to make are to the cell where the drop down is located and to macro names. The items are marked in blue.
How to Save a Worksheet Event Macro
1. Copy the macro using CTRL+C keys.
2. Open your Workbook and Right Click on the Worksheet's Name Tab for the Worksheet the macro will run on.
3. Left Click on View Code in the pop up menu.
4. Paste the macro code using CTRL+V
5. Save the macro in your Workbook using CTRL+S