Refer the below article about ajax call.
You need to check the selected radiobutton as per the condition and call the web method according to the condition.
HTML
<div>
    <label id="lsea1">
        <input type="radio" name="iCheck" id="RBmkv" runat="server" dir="rtl" />RBMKV</label>
    <label id="lsea1">
        <input type="radio" name="iCheck" id="RBdvd" runat="server" />RBDVD</label>
</div>
<div>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript">
        $(function () {
            $('[name=iCheck]').on('change', function () {
                var checkedRadioButton = $(this)[0].value;
                if (checkedRadioButton.toLowerCase() == "rbmkv") {
                    GetCustomers("GetCustomersPageWise", 1);
                }
                else if (checkedRadioButton.toLowerCase() == "rbdvd") {
                    GetCustomers("GetCustomersPageWisedvd", 1);
                }
            });
        });
        function GetCustomers(method, pageIndex) {
            $.ajax({
                type: "POST",
                url: "Default.aspx/" + method,
                data: '{pageIndex: ' + pageIndex + '}',
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function OnSuccess(response) {
                    //do your stuff.
                },
                failure: function (response) {
                    alert(response.d);
                },
                error: function (response) {
                    alert(response.d);
                }
            });
        }        
    </script>
</div>
Code
[WebMethod]
public static string GetCustomersPageWise(string pageIndex)
{
    return ""; //return as per your requirement
}
[WebMethod]
public static string GetCustomersPageWisedvd(string pageIndex)
{
    return ""; //return as per your requirement
}