"Rank classification" in evaluation for multiple choices

Hi,

Thanks for the repo! I was wondering if you would please point out which lines of code are for the "rank classification" idea used for evaluating the multiple-choice style tasks?

The paper describes it like this on Page 6:

> For tasks that involve choosing the correct completion from several options (e.g. multiple choice
question answering), we follow Brown et al. (2020) and use **rank classification** to evaluate our
model: we compute the log-likelihood of each of the target options under the fine-tuned model and
select the option with the highest log-likelihood as the prediction. For simplicity, we do not apply
length normalization to the log-likelihoods of the target options.

Thank you!