B.
The tone is how the author presents the text using their language (think of it as how you would hear their “tone” of voice if they were to read out loud.
Example:
I hate you! I thought I could trust you, but clearly I was wrong. How could you do this to me?
(The tone is angry and accusing, we can see this by the words I used - “hate”, “clearly” - as well as the use of the exclamation point to show anger and force in the language.
