A. he was not able to charm princess mary into marriage
B. he was accused of inciting the serfs to start the fires at smolensk
C. he overheard
I'm pretty sure it is C. Borris overhears the emperor speak of French troops in Russia.
Book 9/ Chapter 3
C. He overheard
"The Emperor, with the agitation of one who has been personally affronted, was finishing with these words:
"To enter Russia without declaring war! I will not make peace as long as a single armed enemy remains in my country!" It seemed to Boris that it gave the Emperor pleasure to utter these words. He was satisfied with the form in which he had expressed his thoughts, but displeased that Boris had overheard it.
"Let no one know of it! " the Emperor added with a frown.
Boris understood that this was meant for him and, closing his eyes, slightly bowed his head. The Emperor re-entered the ballroom and remained there about another half-hour.
Boris was thus the first to learn the news that the French army had crossed the Niemen and, thanks to this, was able to show certain important personages that much that was concealed from others was usually known to him, and by this means he rose higher in their estimation."
War and Peace
