Choosing randomly from a condition with different options

I am new to PsychoPy. I am trying to create a language experiment. A dialogue is presented to subjects. It starts with a scene-setting passage and in this step it has a sentence which gives the context. There are two possible context sentences (negative or positive). Subjects see only one of them. Then subjects read the antecendant and then the answer to that antecendant. There are four possible answers but only one of them will be presented to subjects. The context and the answer will be selected randomly in equal numbers. (e.g. There are 48 experimental items and 24 of them will have positive context.) I was able to construct the experiment with only one context and one answer. But I don’t know how to tell PsychoPy to choose from two different contexts and four different answers.

Thanks in advance,