Where should a question mark be placed in a short citation? According to Modern Language Association (MLA) norms we should use punctuation marks after the page number, within parentheses, that follows the closing quotation mark. For example:


  According to Foulkes's study, dreams may express "profound aspects of
  personality" (184).


But what if a question mark is inherent to the quotation? Example:


  “[t]o what extent do translation theorists engage with the experience
  of translators and how are their theories shaped by what happens in
  practice?” (16)


How should this be cited? Possibilities I can see:


  “[t]o what extent do translation theorists engage with the experience
  of translators and how are their theories shaped by what happens in
  practice” (16)?


Or


  “[t]o what extent do translation theorists engage with the experience
  of translators and how are their theories shaped by what happens in
  practice?” (16).


Which one is correct?
As Peter indicates, the question mark should remain with the original quotation, since it's in the original source material. Therefore, your second example is clearly incorrect. In addition, you still need the period following the citation, to indicate that you are ending the sentence in question. Therefore, you should use the last example.

However, I would also note that, as written, it looks like your example would also require the name of the author along with the parenthetical reference, so it would be more like:


  “[t]o what extent do translation theorists engage ith the experience of translators and how are their theories shaped by what happens in practice?” (Smith 16).