- print_r: documentation ( source)
<?php
$a = array('0' => '0A', '1' => '1A', '2' => '2A');
$b = array('0' => '0B', '4' => '4B', '2' => '2B');
$c = array('0' => '0C', '3' => '3C', '2' => '2C');
$options = $c + $b;
print_r($options);