delete from jgrid using web api Mvc 4

<script type="text/javascript">
        $(document).ready(function () {            

            $("#Jgrid").jqGrid({
                caption: "SubCatagory",
                url: '/api/SubCatagory/GetAllSubcatagoryGrid',
                datatype: "json",
                mtype: 'GET',
                contentType: "application/json; charset-utf-8",
                colNames: ['SubCatagory ID', 'SubCatagory Name', 'SubCatagory Code', 'CatagoryId'],
                colModel: [
                            { key: true, hidden: true, name: 'SubCatagoryId', index: 'SubCatagoryId', editable: true },
                            { key: false, name: 'SubCatagoryName', index: 'SubCatagoryName', editable: true },
                            { key: false, name: 'SubCatagoryCode', index: 'SubCatagoryCode', editable: true },
                            { key: false, name: 'CatagoryId', index: 'CatagoryId', editable: true }

                ],
                pager: jQuery('#pager'),
                rowNum: 10,
                rowList: [10, 20, 30, 40],
                height: '100%',
                viewrecords: true,
                caption: 'SubCatagory List',
                emptyrecords: 'No records to display',
                jsonReader: {
                    root: "rows",
                    page: "page",
                    total: "total",
                    records: "records",
                    repeatitems: false,
                    Id: "0"
                }
            }).navGrid('#pager', { edit: true, add: true, del: true, search: false, refresh: true },
            {
                // edit options
                zIndex: 100,
                url: '/api/SubCatagory/EditSubCatagoryId/',
                closeOnEscape: true,
                closeAfterEdit: true,
                recreateForm: true,
                afterComplete: function (response) {
                    if (response.responseText) {
                        alert(response.responseText);
                    }
                }
            },
        {
            // add options
            zIndex: 100,
            url: "/api/SubCatagory/AddSubCatagoryId/",
            closeOnEscape: true,
            closeAfterAdd: true,
            afterComplete: function (response) {
                if (response.responseText) {
                    alert(response.responseText);
                }
            }
        },
        
        {
            // delete options
            
            zIndex: 100,
            url: "/api/SubCatagory/DeleteSubCatagoryId/", // I want selected Id here using + sign
            datatype: "json",
            mtype: 'Delete',
            contentType: "application/json; charset-utf-8",
            closeOnEscape: true,
            closeAfterDelete: true,
            recreateForm: true,
            msg: "Are you sure you want to delete this task?",
            afterComplete: function (response) {
                if (response.responseText) {
                    alert(response.responseText);
                }
            }
        });

        });
</script>

<table id="Jgrid"></table>
            <div id="pager"></div>