JSON Parse: Not parsing with javascript

I get JSON data with jquery.ajax and dataType is "JSON" But I have some problem

This is my JSON data :

{
    "stock": {
        "head": [
            "name",
            "est",
            "date"
        ],
        "body": [
            {
                "row": [
                    "TEST",
                    "10.58",
                    "2013-09-05 13:37:20"
                ]
            }
        ]
    },
    "year": {
        "head": [
            "name",
            "est",
            "date"
        ],
        "body": [
            {
                "row": [
                    "TEST",
                    "0",
                    "2013-09-05 13:37:35"
                ]
            }
        ]
    }
}

This is my javascript code:

var getdata = $.ajax({
    type     :    'POST',
    url      :    'testjson.php',
    data     :    data,
    dataType :    'json'
});

getdata.done(function(result){

    var queryHead = result.stock.head; // This returns data
    var queryBody = result.stock.body; // But this doesn't return data. Empty

});

JSON data successfully returned, but not being parsed correctly. queryHead works fine but queryBody does not work