Prepaid does not exist in the current context

Hi

  In below code i am getting above error. Secondly i don't want to pass Hardcode values like 160060

var body = "{" + Environment.NewLine +
                        $"    \"origin\" : \"{160060}\"," + Environment.NewLine +
                        $"    \"destination\" : \"{160062}\"," + Environment.NewLine +
                        $"    \"payment_type\" : \"{prepaid}\"," + Environment.NewLine +
                        $"    \"order_amount\" : \"{1000}\"" + Environment.NewLine +
                       "}";

Thanks