how to return the current plugin directory in wordpress

Choose the correct option from the following

Which of the following codes will return the current  plugin directory in wordpress?

 

  1. <?php plugin_basename($file);?>
  2. <?php plugin_basename(‘url’);?>
  3. <?php bloginfo_plugin(‘url’); ?>
  4. <?php content_plugin_url($path);?>

The right answer is :

<?php plugin_basename($file);?>