Please answer the following question: In 1812, in a village near Paris, France, a little boy had a terrible accident. He hit himself in the eye with one of his father's sharp tools, and became blind. His name was Louis Braille, and he was only four years old. He was a clever little boy, and he soon learned to "see" without his eyes. He touched things, or smelled them, or tasted them. His family described things to him. Although he couldn't see people's faces, he learned to recognize their voices. After his seventh birthday, Louis went to the little school in the village. But there weren't any books for him. His classmates read his lessons to him and his sisters helped him with his homework. He learned his lessons well, but he couldn't learn to read or write. In 1819, the village priest told Louis Braille's story to the director of a famous school for blind boys. At this school, boys learned math, grammar, geography, history, and music. And they learned to read! Louis went to the school in Paris in February, 1819. He loved his classes and received high grades. He learned to play the piano and to knit hats and sweaters. And he learned to read -- with his fingers! The raised-print letters in the books at school stood up from the surface of the paper. Louis could feel them with his fingers. He was able to recognize some of them easily, but some of them were difficult. The letters had to be very large, and sometimes there were only a few letters on a page. The books were huge and heavy. And they were expensive. There were only fourteen books in the school library! Louis read the three or four books for his class again and again. He tried to think of a better way to make books for blind people. He experimented with new alphabets. After about three years, Louis invented a system of raised dots. The other students thought Louis's system was wonderful. They were able to read it easily, and they learned to write, too. Today, there are thousands of Braille books for blind people. Louis Braille was only fifteen years old when he invented his wonderful system! Without his eyes, he could also "see" by _ . A) touching things B) smelling or tasting things C) trying to recognize people's voices D) all the above ways
A:
D