Which directory in a user’s home contains configuration files and key rings for GPG?

A.
~/gpg.d/

B.
~/.gpg/

C.
~/.gnupg/

D.
~/gnupg/

E.
~/.gpg.d/

Explanation/Reference:
From the man pages:
The GnuPG home directory [is] "~/.gnupg" if –homedir or $GNUPGHOME is not used