On what grounds does Elizabeth reject Mr. Darcy's proposal of marriage, and how does Mr. Darcy defend himself against her allegations?

Mr. Darcy's Offensive Sense of His Social SuperiorityElizabeth gives three distinct reasons to Mr. Darcy for having rejected his proposal of marriage. Firstly, she says that he has always been speaking to her from a higher level because he is too proud a man and because he has been always acutely conscious of his social superiority over her. Even while making his proposal of marriage, she says,