system: You are an expert security code reviewer. You will be shown a source code file along with a multiple-choice question listing several function or class names from that file. Your task is to identify which one contains the specified CWE vulnerability.

OUTPUT FORMAT: Respond with the single letter of the correct option, wrapped in \boxed{...}. Example: `\boxed{B}`. Output the boxed letter ONLY -- no explanation, no other text.

user: ```python
import inspect
import mimetypes
import urllib

import socket
from socketserver import ThreadingMixIn
from http.server import SimpleHTTPRequestHandler, HTTPServer

import nest_asyncio

PORT = 5000
HOST = socket.gethostname()

class DataTransfer:
    """ TODO: stuff"""
    pass

DATA = DataTransfer()

class HTTPResponse:
    """Object to hold data about the response. No data is given if a GET request is passed."""

    def __init__(self, method, local_data=None):
        """
        Parameters:
                method {[string]} -- The request method. Either GET or POST

        Keyword Arguments:
                data {[dict]} -- The POST request's json data (default: {None})
        """

        self.method = method

        self._original_data = local_data

        if local_data:
            self._json = local_data.get("json")


    async def json(self):
        """Get the response json"""
        return self._json

class ThreadingSimpleServer(ThreadingMixIn, HTTPServer):
    pass

class HTTPRequestHandler(SimpleHTTPRequestHandler):
    """The handler that handles all of our website's requests, and calls the routing functions"""

    def do_GET(self):
        """This function handles the GET requests for the site."""

        if not DATA.bot:
            return self.wfile.write(b"Bot not supplied, wait a few seconds and refresh.")

        path = self.path.replace("/", "")

        if path == "":
            path = "index"

        if path.endswith(".js"):
            self.send_header("Content-type", "application/javascript")

            with open("%s/%s" % (DATA.static_path, path), "r") as file:
                return self.wfile.write(file.read().encode())
        if path.endswith(".css"):
            self.send_header("Content-type", "text/css")

            with open("%s/%s" % (DATA.static_path, path), "r") as file:
                return self.wfile.write(file.read().encode())

        if path in dir(DATA.routing_file):
            route_func = getattr(DATA.routing_file, path)
        else:
            return self.wfile.write(b"404, page not found")

        if not inspect.iscoroutinefunction(route_func):
            raise ValueError("Route function must be a coroutine.")

        try:
            result = DATA.loop.run_until_complete(route_func(DATA.bot, HTTPResponse("GET")))
        except RuntimeError as error:
            if str(error).startswith("Cannot enter into task"):
                pass

        if not isinstance(result, str):
            result = str(result)

        mimetype, _ = mimetypes.guess_type(path)
        self.send_response(200)
        self.send_header("Content-type", mimetype)
        self.end_headers()

        return self.wfile.write(result.encode())

    def do_post(self):
        """This function handles the POST requests for the site."""

        path = self.path.replace("/", "")

        if path == "":
            path = "index"

        if path.endswith(".js"):
            self.send_header("Content-type", "application/javascript")

            with open("%s/%s" % (DATA.static_path, path), "r") as file:
                return self.wfile.write(file.read().encode())
        if path.endswith(".css"):
            self.send_header("Content-type", "text/css")

            with open("%s/%s" % (DATA.static_path, path), "r") as file:
                return self.wfile.write(file.read().encode())

        body = self.rfile.read(int(self.headers.get("Content-Length"))).decode("utf-8").replace("+", " ")
        body = urllib.parse.unquote(body)

        json = {}
        for key_value in body.split("&"):
            key = key_value.split("=")[0]
            value = key_value.split("=")[1]

            json[key] = value

        self.send_response(200)
        self.end_headers()

        response = HTTPResponse("POST", {"json": json})


        if path in dir(DATA.routing_file):
            route_func = getattr(DATA.routing_file, path)
        else:
            return self.wfile.write(b"404, page not found")

        self.send_response(200)

        if not inspect.iscoroutinefunction(route_func):
            raise ValueError("Route function must be a coroutine.")

        try:
            result = DATA.loop.run_until_complete(route_func(DATA.bot, response))
        except RuntimeError as error:
            if str(error).startswith("Cannot enter into task"):
                pass

        return self.wfile.write(str(result).encode())

class App:
    """The main dashcord application"""

    def __init__(self, bot, template_path, static_path, routing_file):
        """
        Parameters
        ----------
        bot
            The commands.Bot / discord.Client object.
        template_path
            The path for your html templates.
        static_path
            The path for your images, javascript and css files.
        routing_file
            The file holding your route functions.

            Usage is ```python
            import routing_file

            App(..., routing_file=routing_file)
            ```
        """

        self.bot = bot
        self.loop = bot.loop

        nest_asyncio.apply(self.loop)

        self.routing_file = routing_file
        DATA.routing_file = routing_file

        self.template_path = template_path
        DATA.template_path = template_path

        self.static_path = static_path
        DATA.static_path = static_path

        bot.dashboard = self

        DATA.bot = bot
        DATA.loop = self.loop

    def render_html(self, fp, **kwargs):
        """
        Load a html file. Supports templating.

        Parameters
        ----------
        fp
            The html file, you don't need to supply the directory path.
        **kwargs
            Keyword arguments in this function are used to give the data to the html file for templating.
        """
        with open("%s/%s" % (self.template_path, fp), "r") as html_file:
            contents = html_file.read()

            for token, body in dict(kwargs).items():
                contents = contents.replace("{{%s}}" % str(token), str(body))

            return contents

    def begin_server(self, host, port):
        while True:
            self.bot.server.handle_request()

    async def start(self, host, port):
        """Start the web server"""
        print("Serving traffic from", host, "on port", port)

        self.server = ThreadingSimpleServer((host, port), HTTPRequestHandler)

        self.bot.server = self.server

        await self.loop.run_in_executor(None, self.begin_server, host, port)

```

Which of the following functions or classes contains a `CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')` vulnerability?

  A) start
  B) do_GET
  C) __init__
  D) begin_server
Answer: B