Functions Learning Mode

What will be the output of the following PHP code?

<?php
    function A1($x)
    {
        switch($x)
        {
        case 1: 
            //this statement is the same as if($x == 1)
            echo 'Case 1 was executed.';
            break;
        case 2: 
            //this statement is the same as if($x == 2)
            echo 'Case 2 was executed.';
            break;
        case 3: 
            //this statement is the same as if($x == 3)
            echo 'Case 3 was executed.';
            break;
        case 4: 
            //this statement is the same as if($x == 4)
            echo 'Case 4 was executed.';
            break;
        default: 
            //this statement is the same as if $x does not equal the other conditions
            echo 'Default was executed.';
            break;

        }
    }
    A1(9);
?>