hi @enrico!
I can think of two approaches

text generation/text2text

Hear as you said you could feed the question and multiple answers to the model and ask it to generate the correct answer.
One way to prepare the dataset for this is to use some delimiter tokens to separate the answers. For ex.
Input text could be
context: context text question: question_text Answer1: answer1_text Answer2: answer2_text
and output text would be the answer text.
You could also delimit the answers using sep  tokens if the models have them.

Frame this as a multiple-choice problem

Here instead of generating correct answer text, you ask the model to identify the correct answer within given answers discriminatively.
You can use the *ForMultipleChoice models classes for this.
You can find multiple choice example script in examples/multiple-choice dir, here 17