Setting default values for a multiple-choice depending on token values is a little trickier because you have to check whether the group has been previously visited.
Assuming the the multiple-choice has question code "Q2" and sub-question codes "SQ1, SQ2, SQ3...":
Place a short text question (code qHidden1) directly after the multiple-choice and use the "Always hide this question" setting. We'll use Expression Manager to set this as an indicator if the page has been previously visited.
Place an equation question (code equation2) directly after qHidden1 with something like this as a value:
Code:
{Q2_SQ2 = (if(is_empty(qHidden1) AND TOKEN:ATTRIBUTE_1 == 'Some value', 'Y', Q2_SQ2))}
Place an equation question directly after equation2 with this as a value: