Where Are User Specific Crontabs Stored

Multiple Choice

Where are user specific crontabs stored?

A) In the database file /etc/crontab.db which is shared by all users.
B) As individual per-user files within /var/spool/cron.
C) As individual per-user files in /etc/cron.user.d.
D) In the .crontab file in the user's home directory.
E) In the file /var/cron/ user-crontab which is shared by all users.