The correct answer is: C. mouse
A mouse is a small handheld device that is used to control the cursor on a computer screen. It is a graphical input device, which means that it is used to interact with graphical user interfaces (GUIs).
A light pen is a pen-shaped device that is used to input data into a computer. It works by detecting light from the computer screen. Light pens are not commonly used today, but they were popular in the early days of personal computers.
A keyboard is an input device that is used to enter text into a computer. It consists of a set of keys that correspond to letters, numbers, and symbols. Keyboards are one of the most common input devices, and they are used for a variety of tasks, such as typing text, entering data, and controlling programs.
A trackball is a pointing device that is used to control the cursor on a computer screen. It consists of a ball that is rotated with the fingers. Trackballs are often used in laptops, as they take up less space than a mouse.
None of the above is a graphical input device.