Answer: The first choice is the correct answer to show the quotation that supports the theme that feelings of guilt are difficult to escape: "O coward that I am, to live so long, /To see my best friend ta'en before my face!"
Explanation: Cassius is talking to Titanius as the enemies are running away. This is the point that Cassius starts to think that he has shown weakness to his men and lost their respect, due to a previous killing Cassius committed. He is now having second thoughts about the murder after the fact. Calling himself a "coward" shows his feeling of guilt. The difficult to escape part is best represented when he says, "to live so long..."