what will be the value of $b?

After running this sort, what will be the value of $b?
<code>
$a = array(‘_!’, ‘def’, 0);
$b = sort($a);
</code>

A.
array(0, ‘def’, ‘_!’)

B.
array(‘_!’, 0, ‘def’)

C.
array(‘def’, 0, ‘_!)

D.
None of the above