If the capitalization for the first sentence wasn't on purpose, it's A. If not, C.
1. On our way to the library, we witnessed (or saw) a flock of birds flying.
2. Lying on the desk, was tom student’s paper.
Irony is a situation in which the statement someway has an outcome that would not have normally been perceived.
"So foul and fair a day" is ironic because if a day has been negative is most likely isn't also seen to be positive.
