Consider the following relational database that stores information about computer hardware products (keys are underlined, field types are omitted): Product (maker, model, type) PC (model, speed, ram, hd, price) Laptop (model, speed, ram, hd, 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

Find the manufacturers who sell PCs with at least the set of all the RAM sizes seen in laptops.