Local and general assortments

Hello Friends,

                     I need a conceptual answer with examples. Assortment Category C? Is that the customer is an external customer or internal customer? Assortment category A and B is for the Store and DC for which we maintain Master data. What about the customer ? Is this customer the consumer or any external store? When do we use  a local assortment? Examples. Thank you

Thanks & Regards

Jove