Populate DropDownList on jQuery Ajax success event in ASP.Net MVC

Hi 

I am developing an application where a form has a dropdown for state city and zipcode. On page load i have called jQuery Ajax and bind the DropDownList with json data.

But when edit the page and again i bind the dropdown with another response from json using jQuery Ajax call, but each and every time all the data is binding with html DropDownList.

In Edit mode i want to bind those data which are coming from get api see the below code.

this Ajax call getting one stateid from backend which i want to bind but all data is getting bind. How to solve this issue. Where i am doing wrong.

$.ajax({
    type: "POST",
    url: '@Url.Action("GetProvider","Provider")',
    data: { UserId: personaldetails.UserId, Role: personaldetails.Role, },
    success: function (response) {
 
        $.each(response, function () {
            $('#firstname').val(response.data.firstName)
            $('#middlename').val(response.data.middleName)
            $('#lastname').val(response.data.lastName)
            $("#datepicker").datepicker("setDate", new Date(response.data.dob));
            $('#datepicker').val(response.data.dob)
            $('#email').val(response.data.email)
            $("#datepickerstartdate").datepicker("setDate", new Date(response.data.dob));
            $('#tax').val(response.data.taxID)
            $('#ptan').val(response.data.pTan)
            $('#npi').val(response.data.npi)
            $('#ssn').val(response.data.ssn)
            $('#phone').val(response.data.phone)
            $('#fax').val(response.data.fax)
            $('#adress1').val(response.data.addressLine1)
            $('#adress2').val(response.data.addressLine2)
            $('#zipcode').val(response.data.zipcode)
            $('#website').val(response.data.website)
            $('#StateID').val(response.data.stateID);
            // $("#StateID").append($("<option></option>").val(response.data.stateID).html(response.data.state));
            $("#CityID").append($("<option></option>").val(response.data.cityID).html(response.data.city));
        });
    },
    failure: function (response) {
        alert(response.responseText);
    },
    error: function (response) {
        alert(response.responseText);
    }
});