The third one. A person uses another's lack of knowledge as proof his argument is correct.
This may be helpful:
https://literarydevices.net/fallacy/
Answer:
instead of saying Sparrow and Liam exchanged stairs across the library you could instead try saying Liam and Sparrows eyes met from across the room or across the library, or not. I think your story's fine, if you want to make it a few more sentence longer then maybe you can put like a little backstory to why Liam and Sparrow are fighting or not it's your story I'm just you know saying maybe if you want a few more sentences it's something to put.
No, abbreviations are not necessary in the thesis.
