Your answer is A. Discard.
Discard means to get rid of or throw away.
Hi!
An author's tone is basically their overall feeling or <em>attitude </em>toward a topic. The tone can be anything from angry, happy, or even sad.
Here's an example:
'And just like that, she left. The walls of melancholy arose; closing in on me once more. I stood alone'.
You would say that the tone in this passage would be of sadness.
Hopefully, this helps you! =)