Explanation:

Short for visual display unit, VDU is an older British term used to describe any device used with computers to display images. ... However, VDU is most commonly used to describe the CRT monitor, a now archaic standard that has been replaced by flat panel displays.
CPU (pronounced as separate letters) is the abbreviation for central processing unit. Sometimes referred to simply as the central processor, but more commonly called a processor, the CPU is the brains of the computer where most calculations take place.
An arithmetic logic unit (ALU) is a digital circuit used to perform arithmetic and logic operations. It represents the fundamental building block of the central processing unit (CPU) of a computer. Modern CPUs contain very powerful and complex ALUs. In addition to ALUs, modern CPUs contain a control unit (CU).