XTemplate: Inserting a variable into a variable

I'm pulling data from a JSON array and I would like to insert one of the data array items into an XTemplate variable in order to determine a final data array item.

Here's a sample (simplified) JSON data array:

Code:

"questions": [
    {
         "questionID": "1",
         "questionNum": "1",
         "questionType": "2",
         "argument": "In what year was the Spanish Armada defeated by English naval forces?",
         "answer": {
             "correctAnswer": "C",
             "optionA": "1558",
             "optionB": "1571",
             "optionC": "1588",
             "optionD": "1592",
             "optionE": "None of the above"
          }
     }
]

Here is some pseudocode to try to illustrate what I am trying to do:

Code:

<tpl if="questionType == 2">
    <div>{answer.option{values.answer.correctAnswer}}</div>
</tpl>

I'm trying to use 'correctAnswer' to determine the option. Basically if the 'correctAnswer' is "C", I would like the TPL to grab the {answer.optionC} data. I'm just not sure how to insert one value into another. Everything I have tried so far has ended up returning the string '{answer.optionC}' instead of parsing it in the TPL. Any help would be appreciated.



XTemplate: Inserting a variable into a variable