下列语句输出的结果是( )
<?php
$bd="sina.";
echo "www.$bdcom";
?>
<?php $bd = "sina."; echo $bd . PHP_EOL; echo "www.$bd~dfgbdfgdfg com". PHP_EOL; echo "www.$bd>dfgbdfgdfg com". PHP_EOL; echo "www.{$bd}dfgbdfgdfg com". PHP_EOL;