What will be the output of the following PHP code?

 <?php  $a = array(red, green, blue);
array_pop($a);
print_r($a);
?> 

A.

Array ( [0] => red [1] => green )

B.

Array ( [0] => green [1] => blue )

C.

Array ( [0] => red [1] => blue )

D.

Array ( [0] => blue [1] => blue )