访问第二，第三级等。使用php从json请求中

Question

我正在尝试使用PHP访问多维数组。我可以使用-

访问第一级

$response['id']

但在定义第二级时遇到了麻烦，因此我可以-

$response['first level']['second level']

这是我的json响应-

Array
(
    [id] => 7181676
    [api_request_id] => 20984853
    [user] => 8305
    [vin] => JTDKN3DU7D1643423
    [make] => Toyota
    [model_name] => Prius
    [model_year] => 2013
    [last_updated] => 2019-02-22T01:08:15.628318Z
    [recall_count] => 1
    [status] => ok
    [recalls] => Array
        (
            [0] => Array
                (
                    [recall_id] => 15753
                    [recall_last_updated] => 2019-02-22T00:33:07.663232Z
                    [recall_age] => 0
                    [nhtsa_id] => 18V684000
                    [oem_id] => J0V
                    [name] => HybridSystem
                    [description] => CollisionRisk
                    [campaign_type] => nhtsa
                    [is_remedy_available] => 1
                    [are_parts_available] => 1
                    [risk_type] => collision
                    [risk_rank] => 5
                    [profit_rank] => 3
                    [overall_rank] => 5
                    [labor_difficulty] => 3
                    [government_id] => 18V684000
                    [is_reviewed] => 1
                    [child] => Array
                        (
                        )
                )
        )
)

我怎么可以说-

$response['profit_rank']