CheckBox for multiple choice in PHP

I'm sorry because I aksed this question 2 times, because I don't find the solution.

I changed an InputText by a Checkbox for a multiple choices. this following my code:

->add('Article', ChoiceType::class, 
    array(
        'choices' => 
            array('A' => 'B',
                        'B' => 'B',
                        'C' => 'C',
                        'D' => 'D',
                        'OTHERS' => 'OTHERS'
            ),
                    'required' => FALSE,
                    'empty_value' => 'ALL',
                    'empty_data' => NULL,
            'multiple' => TRUE,
            'expanded' => TRUE

    )
);

It return next to each other. Please I'm need for your helps. How can I change my code to return a checkbox like this picture ?

Thank you.