The correct answer to this question is D, all of the above. In many countries, a girl's education is the lowest priority due to funding. If the choice for funding is between a girl or a boy, the boy would be selected to attend school. Girls are also less likely to attend school because they are expected to stay and tend to the home.
Many fathers feel if the daughter is educated, she will no longer obey him or care for him. Early marriage is also another main reason. Every year, over 15 million girls are married before they turn 18. Marriage is often seen as a higher priority than learning.