Answer:
A. They believed that educating the poor lower classes could make them rebellious and thus take away the power of the upper classes.
Explanation:
Knowledge is power and a two-way street, As long the upper classes monopolize education and the access to knowledge, they can do as they please with their lower class workers, even violate their rights on a regular basis, as the uneducated lower classes are prevented from learning about their lawful rights because of their illiteracy and lack of critical thinking that usually stems from the habit of reading.
In today's world, it is next to impossible for the upper classes to deny education to the lower classes as their public image would be severely compromised and they would be perceived as "the bad guys in the story." Instead, they have managed to limit education to basic literacy and discouraged lower class people from developing the kind of critical thinking that would enable them to oppose the power of the wealthy people.