In Act IV of The Tragedy of Macbeth, what finally convinces Malcolm that Macduff is loyal?
A. Macduff's professed hatred for Macbeth and those who support him
B. Macduff's noble despair for his country, now under Macbeth's rule
C. Macduff's despair when Malcolm portrays himself as unfit to govern
D. Macduff's profound grief over the murder of his wife and son