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: Vic fuckin my old bitch nunu she acting like she didn't fuck 
Completion A: niggas for real till I saw her dress like this niggas dress like a mary-knoll-wearing-the-g 
Completion B: anything and she was like "Fuck your backside she's fucked, she's going to blow my dick out of my ass if we don't tal
Answer:
Completion B