i have been trying to display the post that contain specific tag.

my query is:  
       
     <form method="post" action="" multiple="multiple">
         <select name="options[]" multiple="multiple">
      <option value="15">mama</option>
      <option value="16">chacha</option>
       <option value="17">Bhatija</option>
      <option value="18">Don</option>

       </select>
      <input type="submit" value="submit" name="submit"/> 
      </form>
          <?php 

                if(isset($_POST['submit'])):
          $options = $_POST['options'];
       $query = new WP_Query( array( 'tag__in' => array( $options ) ) ); 
      //print_r($query);
       while ($query->have_posts()) : $query->the_post(); 
          echo get_the_tile($post->ID);
  
       endwhile;


  unfortunately not working.

   need help to get the list of post by selected tag.