Attached problem uses parserRadioButtons.pl to provide a multiple-choice item [following some free-response items omitted in attachment]. Parts of it use info in second example at http://webwork.maa.org/wiki/MultipleChoiceProblems on our wiki. My current version has two aspects which I hope to fix in a simple fashion:
1) correct choice is always listed first and ordering of others is nearly static while parameter $a is re-randomized
2) labels=>"ABC" and labels=>['A','B',...,'F', 'None'] have no effect on display [but A does show as Correct Answer and my Solution uses $rb->correct_ans() as value of $gInv]
I suspect NchooseK and invert (in PGchoicemacros.pl, but deprecated there) together with the order option for RadioButtons (see http://webwork.maa.org/pod/pg_TRUNK/macros/parserRadioButtons.pl.html) would give me the tools to assemble the pieces with fine control, but I hope something simpler suffices.