D. VISUAL BASIC
Visual Basic (VB) is an event driven programming language and associated development environment from Microsoft for its COM programming model. Visual Basic was derived from BASIC and enables the rapid application development (RAD) of graphical user interface (GUI) applications. Visual Basic allows many additional components to be added to the toolbox. The Microsoft Comm component is used to add a serial communication facility. Here we have used VB also for providing graphical user interface at PC for easy access to display system, password changing and monitoring.