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 django
from core.models import Author, AuthorOrder, Bibtex, Book
from django.shortcuts import get_object_or_404
from rest_framework import serializers
from users.models import User


# -------------------------------------------------------------------
class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = (
            "username",
            "email",
        )


"""
User
"""


def get_login_user(user_id):
    return get_object_or_404(User, pk=user_id)


# -------------------------------------------------------------------
# ===========
#  My Models
# ===========


class AuthorSerializer(serializers.ModelSerializer):
    class Meta:
        model = Author
        fields = (
            "id",
            "name_en",
            "name_ja",
            "affiliation_en",
            "affiliation_ja",
            "mail",
            "modified",
        )

    def create(self, validated_data):
        author = Author.objects.create(**validated_data)
        author.owner = self.context["request"].user
        author.save()
        return author


class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = ("id", "style", "title", "abbr", "modified")

    def create(self, validated_data):
        book = Book.objects.create(**validated_data)
        book.owner = self.context["request"].user
        book.save()
        return book


class BibtexSerializer(serializers.ModelSerializer):
    book = BookSerializer(read_only=True)
    book_id = serializers.IntegerField(max_value=None, min_value=None)

    class Meta:
        model = Bibtex
        fields = (
            "id",
            "language",
            "pub_date",
            "title_en",
            "title_ja",
            "bib_type",
            "volume",
            "number",
            "page",
            "pub_date",
            "book",
            "book_id",
            "book_title",
            "url",
            "fund",
            "modified",
        )

    def create(self, validated_data):
        book_id = validated_data.pop("book_id")
        book = get_object_or_404(Book, pk=book_id)

        try:
            bibtex = Bibtex.objects.create(book_id=book.id, **validated_data)
            bibtex.owner = self.context["request"].user
            bibtex.save()
        except django.db.u0tils.IntegrityError as e:
            raise serializers.ValidationError("DB IntegrityError: {}".format(e))
        return bibtex


class AuthorOrderSerializer(serializers.ModelSerializer):
    bibtex = BibtexSerializer(read_only=True)
    author = AuthorSerializer(read_only=True)
    bibtex_id = serializers.IntegerField(max_value=None, min_value=None)
    author_id = serializers.IntegerField(max_value=None, min_value=None)

    class Meta:
        model = AuthorOrder
        fields = (
            "id",
            "bibtex",
            "author",
            "order",
            "modified",
            "bibtex_id",
            "author_id",
        )

    def create(self, validated_data):
        # Bib
        bib_id = validated_data.pop("bibtex_id")
        bib = get_object_or_404(Bibtex, pk=bib_id)
        # Author
        author_id = validated_data.pop("author_id")
        author = get_object_or_404(Author, pk=author_id)
        # Create New
        try:
            author_order = AuthorOrder.objects.create(
                bibtex=bib, author=author, **validated_data
            )
            author_order.owner = self.context["request"].user
            author_order.save()
        except django.db.utils.IntegrityError:
            raise serializers.ValidationError("DB IntegrityError")
        return author_order

```

Which of the following functions or classes contains a `CWE-209: Generation of Error Message Containing Sensitive Information` vulnerability?

  A) create
  B) BookSerializer
  C) Meta
  D) BibtexSerializer
Answer: A