For example, in this image if user select "East" in dropdown i want to show "Officers East" control in the place "B". If user changes the dropdown to "West", then at the same place "B", i want to show "Officers West" control. (Not in next column or row).
You can find more information in the documentation here.
In your case, to show/hide fields dynamically and keep the layout, you need to use a Grid container.
Add two Grid containers and fields to the form like this: