Training NLP with multiple text input features
Concatenating the whole question and its answers in a RNN could be an option to try, but then always use a reserved special token (or various) to mark where the questions start. E.g. you could concatenate like:

Question text &lt;1> answer 1 &lt;2> answer 2 &lt;3> answer 3 &lt;4> answer 4

where &lt;1>, &lt;2>... are the special tokens so that the model, with enough examples, may be able to understand its meaning.

The "enough examples" is worth stressing, specially as this type of model may require a large complexity (in terms of number of parameters) to make it work, and hence you will need a large enough data set, possibly of the order of the 10k or larger. You can also test some data augmentation by mixing the order of the answers in the input, and of course changing the correct label.