Error while parsing a Json object

From my jQuery file, I call a function from my controller which returns a Json object, as below:

[AcceptVerbs(HttpVerbs.Get)]
        public ActionResult MatrixTypes()
        {

            var matrix = Enum.PricingMatrixType();

            return Json(matrix);

        }

The call is made by the following function, I'm posting only an excerpt that really matters:

 var matrix;

                                            $.get(
                                            MatrixTypeUrl, 
                                            function(data) {
                                                matrix = JSON.parse(data);
                                                for (var i = 0; i < matrix.length; i++) {
                                                    html += String.format('<option value="{0}">{1}</option>', matrix[i].Value, matrix[i].Text);
                                                }

When I press a button on my page, this function gets correctly called, but blows up at the line "matrix = JSON.parse(data);"

The data object has data, I double checked it on the call by debugging.

This was the error I got:

JSON.parse [Break on this error] matrix = JSON.parse(data);

What do you thi开发者_运维知识库nk I can do about this?

EDIT: By using Firebug, I could also confirm that the JSON object is not empty, this is the response of the server:

[{"Text":"Valor Único","Value":"0"},{"Text":"Intervalo","Value":"1"},{"Text":"Valor Adicional","Value":"2"}]

Nevermind this problem, I fixed it. It was missing some calls at the initializer of the jQuery class and so it had errors way before it arrived at the call of JSON.parse(data).