Array
(
    [0] => Array
        (
            [exam_id] => 1
            [exam_ans] => Array
                (
                    [0] => 1
                    [1] => 2
                )

        )

    [1] => Array
        (
            [exam_id] => 2
            [exam_ans] => Array
                (
                    [0] => A
                    [1] => B
                )

        )

)