I believe the answer is A) he is so upset that he loses his last hold on sanity and forces his men into a battle with Malcolm that they cannot win.
He is very sad that Lady Macbeth dies, and says he wishes she had died at a time when he could properly mourn her.
When he leads his men into battle, he says, "The queen, my lord, is dead,"
Hope this helps! Please let me know if I'm wrong :)
