Please fill in 3 blanks ( the consumer end, either end, the supplier end, the centre)

Consider the process-chain-network (PCN) diagram below. The step of assembling the sandwich could be performed either by the service provider or by the customers. Describe how the options compare in terms of efficiency, economies of scale, and opportunity for customization. Moving toward toward would be the highest near of the PCN diagram would tend to increase the efficiency of the process. Moving would tend to benefit more from economies of scale. The opportunity for customization of the diagram