Question (4) (Total: 10+15-25 points) (a) (2.5*4-10 points) Describe 4 schemas or relations or tables that might be used to store information in a social-networking system such as Facebook (b) (15 points) What are the appropriate primary keys in following relations? Also, find appropriate foreign keys based on your chosen primary kays. branch (branch name, branch city, assets) customer (customer name, customer street, customer city) loan (loan number, branch name, amount) borrower (customer name, loan number) account (account number, branch name, balance) depositor (customer name, account number)