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.

Prompt: Thanks for the small flat rate priority boxes. I'll remember to use 
Completion A: this when my next loan gets a lot of interest. Thanks to you the small rates are much lower than at many banks now, and it's also 
Completion B: those for the other priority boxes. I'll also do the "first letter of the alphabet" priority. I've also put together my preferred priority bo
Completion A