3. (50 points) Normalization Consider the following ComputerSales relation (table) hold details of sales related data for various computer models in a retail chain's database. ComputerSales (ModelNumber, ModelName, StoreNumber, StoreManager, StoreCity, NumberSold, GrossSales, DCNumber, ManufacturerName, DCAddress) Suppose that the following functional dependencies are present in the ComputerSales relation FD1: ModelNumber -> ModelName, ManufacturerName FD2: StoreNumber -> StoreName, StoreManager, StoreCity FD3: ModelNumber, StoreNumber -> NumberSold, GrossSales FD4: StoreCity -> DCNumber, DCAddress a) Determine the primary key of the ComputerSales relatiorn b) Decompose CustomerSales into 2NF, and then into 3NF relations. Clearly identify the primary key for each of the newly formed relations. Using the 3NF relations, construct an ER diagram. Clearly state any assumptions made. c)