PHP Basics Learning Mode

Consider the following script: 


<?php
    function myfunction($a, $b = true)
    {
        if($a && !$b) {
            echo "Hello, World!\n";
        }
    }
    $s = array(
         0 => "my",
         1 => "call", 
         2 => '$function', 
         3 => ' ',
         4 => "function", 
         5 => '$a',
         6 => '$b', 
         7 => 'a',
         8 => 'b',
         9 => ''
        );
    $a = true;
    $b = false;
    /* Group A */
    $name = $s[?].$s[?].$s[?].$s[?].$s[?].$s[?];
    /* Group B */
    $name(${$s[?]}, ${$s[?]});
?>

Each ? in the above script represents an integer index against the $s array. In order to display the Hello, World! string when executed, what must the missing integer indexes be?
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