array(2406) {
    [0]=>
    array(2) {
    ["brand"]=>
    string(4) "Mazda"
    ["model"]=>
    string(9) "CX-4"
    }
    [1]=>
    array(2) {
    ["brand"]=>
    string(4) "Mazda"
    ["model"]=>
    string(19) "CX-5"
    }

    [...]

    [120]=>
    array(2) {
    ["brand"]=>
    string(12) "Mercedes"
    ["model"]=>
    string(10) "E-class"
    }
    [121]=>
    array(2) {
    ["brand"]=>
    string(12) "Mercedes"
    ["model"]=>
    string(10) "S-class"
    }
    [122]=>
    array(2) {
    ["brand"]=>
    string(9) "Volkswagen"
    ["model"]=>
    string(10) "Golf"
    }
    [123]=>
    array(2) {
    ["brand"]=>
    string(9) "Volkswagen"
    ["model"]=>
    string(10) "Polo"
    }
    [124]=>
    array(2) {
    ["brand"]=>
    string(9) "Volkswagen"
    ["model"]=>
    string(10) "Touareg"
    }
}

"Mazda" : { // the brand
        "CX-4",// the list of brand’s models
        "CX-5",
    },
    "Mercedes" : {
        "E-class",
        "S-class",
    },
    "Volkswagen" : {
        "Golf",
        "Polo",
        "Touareg",
    },

foreach($row as $brand => $key){
            echo ""$brand" : {n";
                print $key[model];

            echo "},n";
            }

"Mazda" : {
CX-4},
"Mercedes" : {
E-class},
"Volskwagen" : {
Golf},