code: public function getSourceOptions(Contao\DataContainer $dc)
  	{
  		if ($this->User->isAdmin)
  		{
  			return array('default', 'internal', 'article', 'external');
  		}
  
  		$arrOptions = array('default');
  
  		// Add the "internal" option
  		if ($this->User->hasAccess('tl_news::jumpTo', 'alexf'))
  		{
  			$arrOptions[] = 'internal';
  		}
  
  		// Add the "article" option
  		if ($this->User->hasAccess('tl_news::articleId', 'alexf'))
  		{
  			$arrOptions[] = 'article';
  		}
  
  		// Add the "external" option
  		if ($this->User->hasAccess('tl_news::url', 'alexf'))
  		{
  			$arrOptions[] = 'external';
  		}
  
  		// Add the option currently set
  		if ($dc->activeRecord && $dc->activeRecord->source != '')
  		{
  			$arrOptions[] = $dc->activeRecord->source;
  			$arrOptions = array_unique($arrOptions);
  		}
  
  		return $arrOptions;
  	}
docs: Add the source options depending on the allowed fields (see #5498)
  
  @param Contao\DataContainer $dc
  
  @return array