I would say D. because all of the others are basically answering the entirety of the speech. If you would discuss ways to increase the literacy rates in the U.S. you would need to go over it last after you explain why the U.S. is so illiterate.
Santosh would have been happier if he had decided to stay in India. He would be happier with his family and his religion more despite being poor there.
He thought he would have a better life in Washington. He was able to earn more money in Washington in exchange of his cultural identity. Santosh was forced to adapt the American Culture and marry someone he doesn't love for the sake of a better life.
Scout's age is very important because it shows how a kid perceives the world and this kid isn't racist and doesn't understand what the big fuss is about. It's important to narrate like this because it shows that we should be like Scout and not allow our prejudice to obstruct our vision.
Democratic People's Republic of Korea (also known as North Korea).