参考错误：未定义 url

如何解决参考错误：未定义 url

            const express = require("express");
            const request = require("request");
            const https = require("https");
            const app = express();
            app.use(express.static("public"));
            app.use(express.urlencoded({extended: true}));
            app.use(express.json());
            app.get("/",function(req,res) {res.sendFile(__dirname+"/index.html");});
            app.post("/",res) {
                const fname = req.body.fname;
                const lname = req.body.lname;
                const email = req.body.emai
                var data = {members:{
                        email_address: email,status: "Subscribed",Merge_fields:{FNAME: fname,LNAME: lname}}]};
                const JSONData = JSON.stringify(data);
                var URL = "https://us6.api.mailchimp.com/3.0/lists/f8e0ce8997/";
                const options = {
                    method: "POST",auth: "abhi: 1ddd76da29dfa0a949ac7530bb861f5d-us6"}
                const request = https.request(url,options,function(response) {
                    response.on("data",function (data) {
                        console.log(JSON.parse(data));
                    });});request.write(JSONData);request.end();
            });
            app.listen(3000,function(){ 
            });

请帮我解决这个错误。我不知道为什么会这样。我检查了 url，api 密钥， 观众 id 但没有一个错误，但我收到了这个错误。

ReferenceError: url is not defined
        at D:\WebDev\NewsLetter\app.js:46:35
        at Layer.handle [as handle_request]