Are you speaking about the Greek mythology?
Answer:
Letter c. projecting a computer image on to a screen.
Explanation:
Video projectors are of frequent use in classrooms, conference rooms, and theaters, especially movie theaters. They are electronic devices capable of taking audio/visual inputs and then projecting them (output) as a video onto a flat surface. That surface can be a white screen or even a wall, for that matter. The output video can be much larger than the original images.
4 meters. That's 400 centimeters which is clearly greater than 28 cm.
