Consider the following database schema that is part of a larger database and stores information about electronic products (that in our case can be either PC, Laptop or Printer.) Product (maker, model, type) PC (model, speed, ram, hdd, price) Laptop (model, speed, ram, hdd, screen, price) Printer (model, color, type, price) The Product relation gives the manufacturer, model number and type (PC/laptop/printer) of various products. The PC relation gives for each model number that is a PC, the speed (of the processor, in gigahertz), the amount of RAM (in GB), the size of hard disk (in GB), and the price. The Laptop relation is similar, with screen size included. The Printer relation records whether it is a color printer or not (Yes/No), the type (laser/ink-jet), and the price. Write the following queries in Relational Algebra: 1. Find the Laptop models for the Laptops that have at least 8 GBs of RAM. 2. Find the manufacturers that make laser printers. 3. Find the manufacturers that make PCs but not Laptops. 4. Find the manufacturer(s) of the cheapest Laptop(s) (smaller price)