如何在Yii框架2.0中选择dropdownList的默认选项

Below is my code snippet of Yii framework 2.0 ActiveField/DropdownList

$form = ActiveForm::begin();

    foreach ($settings as $index => $setting) {

        for($i = 0; $i < 3; $i++) {
             echo $form->field($setting, "[$index]option[]")->dropdownList(['0' => 'A', '1' => 'B', '2' => 'C']) ?>
        }
    }

ActiveForm::end();

With the for loop above I have a dynamic set of models within a form and each model has 3 dropdownLists of the same property option which can be submitted as an array. When $i = 0 I would like to select option A as default. When $i = 1 I would like to select option B as default and When $i = 2 I would like to select option C as default.

How can I do that?

Try:

   for($i = 0; $i < 3; $i++) 
    {
        $model->option[$i] = "$i";
        echo $form->field($model, "option[$i]")
             ->dropdownList(['0' => 'A', '1' => 'B', '2' => 'C']);
   }

echo $form->dropDownList(

$model,

'country_id',

Country::items(),

array(
    'empty'=>'--Select a country--')
);