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 collections
import contextlib
import datetime
import multiprocessing
import os
import shutil
import sys
import socket
import tempfile
import threading

import jinja2
import yaml


@contextlib.contextmanager
def temp_dir():
    path = tempfile.mkdtemp(dir=os.environ.get('TEMP'))
    try:
        yield path
    finally:
        shutil.rmtree(path)


@contextlib.contextmanager
def autoremoved_file(path):
    try:
        with open(path, 'w') as handle:
            yield handle
    finally:
        os.unlink(path)


@contextlib.contextmanager
def cd(new_cwd):
    old_cwd = os.getcwd()
    os.chdir(new_cwd)
    try:
        yield
    finally:
        os.chdir(old_cwd)


def get_free_port():
    with contextlib.closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
        s.bind(('', 0))
        s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        return s.getsockname()[1]


def run_function_in_parallel(func, args_list, threads=False):
    processes = []
    exit_code = 0
    for task in args_list:
        cls = threading.Thread if threads else multiprocessing.Process
        processes.append(cls(target=func, args=task))
        processes[-1].start()
    for process in processes:
        process.join()
        if not threads:
            if process.exitcode and not exit_code:
                exit_code = process.exitcode
    if exit_code:
        sys.exit(exit_code)


def read_md_file(path):
    in_meta = False
    meta = {}
    meta_text = []
    content = []
    if os.path.exists(path):
        with open(path, 'r') as f:
            for line in f:
                if line.startswith('---'):
                    if in_meta:
                        in_meta = False
                        meta = yaml.full_load(''.join(meta_text))
                    else:
                        in_meta = True
                else:
                    if in_meta:
                        meta_text.append(line)
                    else:
                        content.append(line)
    return meta, ''.join(content)


def write_md_file(path, meta, content):
    dirname = os.path.dirname(path)
    if not os.path.exists(dirname):
        os.makedirs(dirname)

    with open(path, 'w') as f:
        if meta:
            print('---', file=f)
            yaml.dump(meta, f)
            print('---', file=f)
            if not content.startswith('\n'):
                print('', file=f)
        f.write(content)


def represent_ordereddict(dumper, data):
    value = []
    for item_key, item_value in data.items():
        node_key = dumper.represent_data(item_key)
        node_value = dumper.represent_data(item_value)

        value.append((node_key, node_value))

    return yaml.nodes.MappingNode(u'tag:yaml.org,2002:map', value)


yaml.add_representer(collections.OrderedDict, represent_ordereddict)


def init_jinja2_filters(env):
    import amp
    import website
    chunk_size = 10240
    env.filters['chunks'] = lambda line: [line[i:i + chunk_size] for i in range(0, len(line), chunk_size)]
    env.filters['html_to_amp'] = amp.html_to_amp
    env.filters['adjust_markdown_html'] = website.adjust_markdown_html
    env.filters['to_rfc882'] = lambda d: datetime.datetime.strptime(d, '%Y-%m-%d').strftime('%a, %d %b %Y %H:%M:%S GMT')


def init_jinja2_env(args):
    import mdx_clickhouse
    env = jinja2.Environment(
        loader=jinja2.FileSystemLoader([
            args.website_dir,
            os.path.join(args.docs_dir, '_includes')
        ]),
        extensions=[
            'jinja2.ext.i18n',
            'jinja2_highlight.HighlightExtension'
        ]
    )
    env.extend(jinja2_highlight_cssclass='syntax p-3 my-3')
    translations_dir = os.path.join(args.website_dir, 'locale')
    env.install_gettext_translations(
        mdx_clickhouse.get_translations(translations_dir, 'en'),
        newstyle=True
    )
    init_jinja2_filters(env)
    return env

```

Which of the following functions or classes contains a `CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')` vulnerability?

  A) temp_dir
  B) init_jinja2_env
  C) get_free_port
  D) read_md_file
Answer: B