Instead of this:

answer[0]="blah"
answer[1]="blah"
answer[2]="blah"
answer[3]="blah"

Do this:
answer=ds_list_create();
ds_list_add(answer,"blah");
ds_list_add(answer,"blah");
ds_list_add(answer,"blah");
ds_list_add(answer,"blah");


And then when you're shuffling:
var templist;
templist=ds_list_create();
ds_list_shuffle(templist);

//display the choices
draw_text(0,0,ds_list_find_value(templist,0));
draw_text(0,0,ds_list_find_value(templist,1));
draw_text(0,0,ds_list_find_value(templist,2));
draw_text(0,0,ds_list_find_value(templist,3));

ds_list_destroy(templist);