But when I try this in WeBWorK version 2.12, I still get the options on separate lines vertically, but with a comma between them.

Here is my problem code. Note that I currently still have a regular multiple choice question first. The RadioButtons element is in the second part of the question.

DOCUMENT();

loadMacros(

"PGstandard.pl",

"MathObjects.pl",

"PGunion.pl",

"parserMultiAnswer.pl",

## "PGcourse.pl",

"PGchoicemacros.pl",

"parserRadioButtons.pl"

);

TEXT(beginproblem());

$showPartialCorrectAnswers = 1;

######################

# SETUP #

$diagram = Image('imageP3-6Main.gif',size=>[400,400],tex_size=>400);

$diagrama = Image('imageP3-6a.gif',size=>[188, 251],tex_size=>300);

$diagramb = Image('imageP3-6b.gif',size=>[188, 251],tex_size=>300);

$diagramc = Image('imageP3-6c.gif',size=>[188, 251],tex_size=>300);

$diagramd = Image('imageP3-6d.gif',size=>[188, 251],tex_size=>300);

$mc = new_multiple_choice();

$mc -> qa (

"a. The contour plot of a function \(f(x, y)\) is shown below along with a blue constraint curve. Which of the four 3D graphs shows a surface plot of this function \(f(x, y)\) and the correct projection of the constraint curve onto the surface?",

"D");

$mc -> makeLast(

"A",

"B",

"C",

"D",

"None of the 3D graphs represent \(f(x, y)\) and this constraint correctly.");

$radio = RadioButtons(["0","1","2","3","4","5","6","More than 6."], "6", separator=>"");

# END SETUP #

######################

######################

# MAIN TEXT #

Context()->texStrings;

BEGIN_TEXT

\{$mc -> print_q()\}

$PAR

\{ColumnTable($mc -> print_a().$BR,

$diagram, indent=>10, separation=>30, valign=>"TOP")\}

\{

BeginTable(spacing=>5).

AlignedRow(["A. ".$diagrama, "B. ".$diagramb, "C. ".$diagramc, "D. ".$diagramd]).

EndTable()

\}

$PAR

b. For the function \(f(x, y)\) in the previous question, how many local extrema does \(f(x, y)\) have if you restrict the input points of \(f\) to points on the given ellipse constraint curve?

$PAR

\{$radio->buttons\}

END_TEXT

Context()->normalStrings;

# MAIN TEXT END #

######################

#############################

# ANSWER EVALUATION #

$showPartialCorrectAnswers = 0;

ANS( radio_cmp( $mc->correct_ans() ) );

ANS($radio->cmp());

# ANSWER EVALUATION END #

#############################

ENDDOCUMENT();