my arrays/select are not posting with my form

html:

{% extends 'base.html' %}
{% block content %}
<!DOCTYPE html>
<html>

<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>Create a Recipe</title>
  <script   src="https://code.jquery.com/jquery-3.5.1.min.js"   integrity="sha256-9/aliU8dGd2tb6OSsuzixeV4y/faTqgFtohetphbbj0="   crossorigin="anonymous"></script>
  <script>

  $(document).ready(function() {

      // process the form
      $('form').submit(function(event) {
          // get the form data
          // there are many ways to get this data using jQuery (you can use the class or id also)
          var formData = {
              'title'              : $('input[name=T]').val(),
              'tags'             : $('select[name=tags]').val(),
              'ingredients'    : $('select[name=ingredients]').val(),
              'time_minutes'    : $('input[name=Time]').val(),
              'price'    : $('input[name=P]').val(),
              'link'    : $('input[name=link]').val(),
          };

          // process the form
          $.ajax({
              type        : 'POST', // define the type of HTTP verb we want to use (POST for our form)
              url         : '/api/recipe/recipes/', // the url where we want to POST
              data        : formData, // our data object
              dataType    : 'json', // what type of data do we expect back from the server
                          encode          : true  
          })
              // using the done promise callback
              .done(function(data) {

                  // log data to the console so we can see
                  console.log(data);

                  // here we will handle errors and validation messages
              });

          // stop the form from submitting the normal way and refreshing the page
          event.preventDefault();
      });

  });
  </script>
</head>

<body class="">

  <form method="POST">
    {% csrf_token %}
    <br>
    <label for="T">Title: </label>
    <input type="text" name="T" value="">
    <br>
    <label for="Ingr">Ingredients: </label>
    <select multiple name="ingredients">
      {% for ing in Ing %}
      <option value="{{ing.pk}}">{{ing}}</option>
      {%endfor%}
    </select>
    <br>
    <label for="Tag">Tags: </label>
    <select multiple name="tags">
      {% for tag in Tag %}
      <option value="{{tag.pk}}">{{tag}}</option>
      {%endfor%}
    </select>
    <br>
    <label for="Time">Time: </label>
    <input type="text" name="Time" value="">
    <br>
    <label for="P">Price: </label>
    <input type="text" name="P" value="">
    <br>
    <label for="link">Link: </label>
    <input type="text" name="link" value="">
    <br>
    <input type="submit" name="submit" value="Post">
  </form>


</body>

</html>
{%endblock%}

this is my HTML I am posting this form to my rest API all the form is posting except the arrays/select are posting as null/0 here is what's getting posted/data console:

id: 57 ingredients: Array(0)

length: 0

proto: Array(0)

link: "recipe.com"

price: "3.00"

tags: Array(0)

length: 0

proto: Array(0)

time_minutes: 20

title: "oOao"

proto: Object

as you can see the ingredients and tags which are arrays aren't posting even if I choose a option.