Set Selected with PHP without Javascript - Adding “selected” attribute to the selected option in PHP

selected.php

<select>
    <?php 
        //init array with key value pairs 
        $purchase_type = array(
            '1' => 'White Rice',
            '2' => 'Red Rice',
            '3' => 'Wheat',
            '4' => 'Packets',
            '5' => 'Firewood'
        );

        foreach($purchase_type as $key => $single) {
            
            //echo <option value="YOUR_VALUE
            echo "<option value=".$key;
            
            //if $YOUR_RETURN_VALUE matches our key echo selected 
            if($YOUR_RETURN_VALUE == $key){ echo " selected"; }
            
            //option open in line 14 close bracket here
            echo '>';
            
            //print your value
            echo $single;
            
            //close option
            echo "</option>";
        }
    ?>
</select>

<!--check explain here - https://goo.gl/DtRGH7 -->