Make a 2D-array, fill it with the correct and with the entity- or bitmap-pointer:
var question[5][3]; //2D-Array, for 5 questions
...
function question_fill()
{
...
//fill the array for the first question
question[0][0] = 1; //the right answer is 1
question[0][1] = bmap_create("question.bmp"); //question-bitmap
question[0][2] = ent_create("answer_entity.mdl",nullevctor,NULL); // answer-entity
...
}
...
function question_ask()
{
var random_number = integer(random(4.9)); //make it random
...
if(my_answer == question[random_number][3])
{
((ENTITY*)question[0][2]).alpha = 100;
}
...
}
This example isn't complete, just to show you how you could do that. ^^
There are more ways, I guess, but I would do it that way.

Hope it helps...
~greets