The new Multi parameter allows you to create multiple choice questions that randomise the order of the answers. This means that your multiple choice question can have answers and distractors that vary due to the parameters used AND the correct answer can change with each regeneration.

The full documentation for the Multi parameter is to complex to be included in this post but is available here:

https://efofex.com/documentation/index.html?multi_parameters.htm

The easiest way to create a multichoice question is to use one of the questions available in FX Library.