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: dude wtf lol IF YOU FUCK IN CHURCH YOU DONT 
Completion A: EVEN HAVE TO HAVE YOUR HEAD SHED AND STICKED TO A WALL YOU HAVE SOME THINGS TO FIND OUT SO CHECK THIS OUT 
Completion B: KNOW WHAT JESUS IS FUCKING BING LONELYI'm really not that happy with these two videos.So fa
Answer:
Completion A