Yes, you are correct. The right answer here is D -- the revolutionary leaders were from the educated middle class. If you think about it, that makes a lot of sense. Here's why:
If you were a slave or if you were from the working class, how were you ever going to be able to influence other people? You wouldn't have the time or the liberty to go around convincing other people to believe in your ideas and you wouldn't have enough time or education to think of many ideas.
If you were a noble or part of the clergy, you would be more likely to like the status quo because you were already in the top levels of society.