NEED HELP WITH PART C.

Using this data, state assumptions about functional dependencies among the columns of data. Justify your assumptions on the basis of these sample data and also on the basis of what you know about retail sales. A. Given your assumptions in part A, comment on the appropriateness of the following designs: 1. CUSTOMER (Name, Phone, Email, InvoiceNumber, InvoiceDate, PreTaxAmount) 2. CUSTOMER (Name, Phone, Email, Invoice Number, InvoiceDate, PreTaxAmount) 3. CUSTOMER (Name, Phone, Email, InvoiceNumber, InvoiceDate, PreTaxAmount) 4. CUSTOMER (CustomerlD, Name, Phone, Email, InvoiceNumber, InvoiceDate, B. PreTaxAmount) 5. CUSTOMER (Name, Phone, Email) and PURCHASE (Invoice Number, InvoiceDate, PreTaxAmount) 6. CUSTOMER (Name, Phone, Email) and PURCHASE (Invoice Number, InvoiceDate, PreTaxAmount, Email) 7. CUSTOMER (Name, Email) and PURCHASE (Invoice Number, Phone, InvoiceDate, PreTaxAmount, Email) D-5 Database Concepts James River Jewelry Project Questions Appendix D Modify what you consider to be the best design in part B to include a column called AwardPurchaseAmount. The purpose of this column is to keep a balance of the customers purchases for award purposes. Assume that returns will be recorded, with invoices having a negative PreTaxAmount. C