Question on functions

Consider the following code block:

<?php
function &myFunction() {
$string = "MyString";
var_dump($string);

return ($undefined);
}

for($i = 0; $i < 10; $i++) {
$retval = myFunction();
}
?>

This code block's behavior has changed between PHP 4 and PHP 5. Why?


Answer...
None of the above
This could would cause an automatic segmentation fault in PHP 4
This code would throw a syntax error in PHP 4
Returning an undefined variable by reference in PHP 4 would cause eventual memory corruption
You could not return undefined variables by reference in PHP 4
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