I like to put questions in two stages. Example

stage1: which method do you use to integrate $x e^x$ (multiple choice/checkbox)

  a) int. by parts
  b) substitution 
  c) direct primitive known
  d) decompose rational function in elementary fractions

if the right answer (here a) is given

stage 2: to apply int. by parts we need to decompose $f(x) = x e^x = u'(x) v(x)$. How? (another choice box)

  a)  $u'(x) = x, v(x) = e^x$
  b)  $u'(x) = e^x, v(x) = x$
  c)  $u'(x) = 1, v(x) = x e^x$
  d)  another wrong answer

I'd like to prepare dozens of such questions (where only the function and stage 2 change) and randomize them. I tried with STACK but it is too complicated (I would need a week for a single question). an someone help with one running example to learn from it?