Part 1. Definition
Given a prompt and two completions from a language model, select the completion that is the most fluent with respect to continuing the prompt. Fluency is defined by coherency and ease of understanding, not necessarily grammatical correctness. Generate either Completion A or Completion B.
Part 2. Example
Prompt: Im 99 percent sure it was someone being an 
Completion A: accomplice , or maybe just plain old con man . whatever it was , it 's over . " 
Completion B: asshole, your right?) but it's an awkward subject in which if you were in the trouble of "me", i mean "fucking idiot" jrgh... i dunno...I guess you are (in a legal context) not a stupid
Answer: Completion A
Explanation: This prompt-completion pair is more fluent because it is more easy to follow and is a realistic statement.
Part 3. Exercise
Prompt: Lez ur a jerk ass! well u neva told me 
Completion A: he is u r good friend but u is wrong for tellin me his name on ur phone ur name is not cool ur cool u is a jerk 
Completion B: to do something and i didnt tell him u neve tried this on me i never knew u neve tried that on me but i dont nev
Answer:
Completion B