Final answer:
The correct size classifications for computers are mainframe, mini, and micro. Minicomputers made technology accessible to smaller entities, and microcomputers, or personal computers, became widespread due to microchip advancements.
Step-by-step explanation:
The size classifications of computers traditionally include mainframe, mini, and micro computers. Among the provided options, the correct one is C. Mainframe, mini, micro. Mainframes are large computers often used by organizations for bulk data processing, like census or enterprise resource planning. Minicomputers, which gained popularity thanks to companies like Digital Equipment Corporation, offered a smaller and more affordable option for smaller businesses and university labs. Eventually, the development of the microchip paved the way for microcomputers or personal computers, significantly reducing the size and cost of computers and making them accessible to consumers and smaller businesses.