Answer:
C. He thought reading was important.
Step-by-step explanation:
After reading the text, we are able to strike out a few answers right off the bat with particular sentences.
Since Louis "played the organ and cello", we know that he didn't have a hard time learning music, so A is out.
There is no mention of Louis' liking of audio books and recordings in the text. It's only mentioned in the sentence: "Even with the invention of audio books and recordings...", which only serves as a conclusion to the passage and doesn't illustrate that Louis likes them. B is out.
The sentence "For ideas, he studied codes used by the military", rules out letter D, since he didn't create the codes he studied. That would be counterproductive.
Therefore, Louis' creation of the Braille system makes C the correct answer. You can also conclude this just from the statement: "He wanted to be able to read as quickly as people with sight." Why else would Louis want this if he didn't think reading was important?