Which format was used for movies of the 1910 and 1920

Between 1910's and 1920's the format of black and white silent films were used.

Known as silent movies, the films produced in this format were produced entirely by images. These films had complex arguments that were represented only by means of images, occasionally dialog boxes or direction known as Intertitles were incorporated, as a way to clarify the situation. In some cinemas, there was a piano or organ that was played while watching the movie, but these productions did not have any kind of built-in sound.

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Ithink the answer is d.

It should be at the center of any map going vertically: the prime meridian, as it passes through greenwich,  england, is considered 0 degrees longitude