radio button null value

<form>
  <fieldset>
    <legend>Please select your preferred contact method:</legend>
    <div>
      <input type="radio" id="contactChoice1" name="contact" value="email" />
      <label for="contactChoice1">Email</label>
      <input type="radio" id="contactChoice2" name="contact" value="phone" />
      <label for="contactChoice2">Phone</label>
      <input type="radio" id="contactChoice3" name="contact" value="null" />
      <label for="contactChoice3">Null</label>
    </div>
    <div>
      <button type="submit">Submit</button>
    </div>
  </fieldset>
</form>
<pre id="log"></pre>

  Forms\Components\Radio::make('contact_preference')
                ->label(__('Choose Plan'))->columnSpanFull()
                ->options([
                    'email' => 'Email',
                    'phone' => 'Phone',
                    null => 'No preference'
                ])