Which one of the following, if placed after sentence 12, would be the most effective concluding sentence for the essay?

Directions for the question:

The following passage is an early draft of an essay. Some parts of the passage need to be rewritten. Read the passage and select the best answer for the question that follows. Keep in mind that some questions are about particular sentences or parts of sentences and ask you to improve sentence structure or word choice. Other questions ask to consider organization and development. In choosing the answer, follow the requirements of standard written English.

(1) Even if Louis Braille died when he was only forty-three years old he succeeded in devising a system of reading and writing for the blind which is now taught all over the world. (2) Braille lost his sight accidentally as a child. (3) Nevertheless, he was able to complete his education at a school for the blind in Paris and become a teacher. (4) In his day, the few books that were available for blind people were printed in big, raised type. (5) The letters used were those of the ordinary alphabet. (6) The reading of such books required immense effort. (7) Not only that, writing was almost impossible for a blind person was still restricted to an alphabet which was extraordinarily difficult to reproduce on paper.

(8) Braille’s idea was to use raised dots instead of letter. (9) He evolved a system which made use of only six dots in all. (10) By various combinations of these dots it not only proved possible to represent each letter in the alphabet but punctuation marks, numbers and musical notations as well. (11) Reading and writing have thus been enormously simplified. (12) The sensitive fingers of a blind person can travel rapidly over the dots: and there is a small machine, something like a typewriter, which enables the blind to write quickly and clearly.