1. Convert the following ER diagram into a relational schema: ID city supplier name delivery_timestamp 8 supplied quantity ID item name 2. Write the following queries in "Relational Algebra" (No SQL, No Calculus): a) List all suppliers (ID and name) who supply item "Bolt". b) List all items (ID and name) supplied by both S2 and S4. c) For each supplier, list its ID, name, and the total quantity supplied by the supplier.