When developing the cells for a focused factory, it is recommended that you start the cell design and factor layout conversion work with final assembly, then do subassembly cells, and end with component parts fabrication. Select the best rationale (the most important reason) for doing it this way.Assembly must be created first so that deliveries to the external customer are not interrupted during the factory conversion projects.This approach mirrors the pull system, and establishes the domand that the up-stream cells must meet.Assembly operations typically take the most floor space, so it is important to radiate the other cells out from it.Assembly operations tend to be labor-intensive, so the assembly cell needs the most attention.