What will be the output of the following PHP code?<br/>$a1 = array("red", "green");<br/>$a2 = array("blue", "yellow");<br/>$a3 = array_merge($a1, $a2);<br/>$a4 = array("a", "b", "c", "d");<br/>$a = array_combine($a4, $a3);<br/>print_r($a);
YOUR ANSWER : ?