Is there a way of including the "set" of all (distinct) elements in the list $L3 as options for the multiple choice, without repeats?

Any help appreciated.

Thank you.

DOCUMENT();

loadMacros(

"PGstandard.pl",

"PGchoicemacros.pl",

"MathObjects.pl",

"contextFraction.pl",

);

TEXT(beginproblem());

Context("Numeric");

$a = random(0,5,1);

Context("Fraction-NoDecimals");

Context()->flags->set(

reduceConstants => 0,

reduceConstantFunctions => 0,

);

$a1 = Formula("(1+sqrt(3))/2");

$a2 = Formula("sqrt(2)");

$a3 = $a1;

$a4 = Formula("(sqrt(3)-1)/2");

$a5 = Formula("0");

$a6 = Formula("(1-sqrt(3))/2");

@L1 = (30,45,60,120, 135, 150,);

@L2 = (150,135,120,60, 45, 30);

@L3 = ($a1,$a2,$a3,$a4, $a5, $a6);

Context()->texStrings;

$radio=new_multiple_choice();

$radio->qa("\( \displaystyle \cos($L1[$a]^\circ)+ \sin($L2[$a]^\circ) =\) $BR ", "\(\displaystyle $L3[$a] \)$BR");

$radio->extra("\(\displaystyle $L3[0]\) $BR", "\(\displaystyle $L3[1] \)$BR","\(\displaystyle $L3[3]\)$BR","\(\displaystyle $L3[4]\)$BR","\(\displaystyle $L3[5]\)$BR");

$radio->makeLast("None of the above.");

BEGIN_TEXT

$BR

\{$radio->print_q()\}

\{$radio->print_a()\}

END_TEXT

Context()->normalStrings;

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

BEGIN_SOLUTION

$PAR Solution $PAR

END_SOLUTION

COMMENT('MathObject version');

ENDDOCUMENT();