Which of the following directories in a user's home contains configuration files and key rings for GPG?

`~/gpg.d/` is not the standard or correct default directory for GPG configuration and keyrings.

`~/.gpg/` is not the standard or correct default directory for GPG configuration and keyrings.

By default, GPG stores all its user-specific configuration files, public and private keyrings, and trust database within the `~/.gnupg/` directory, adhering to the common Unix convention for hidden configuration directories.

`~/gnupg/` is incorrect because configuration directories are typically hidden (prefixed with a dot) in Unix-like systems.

`~/.gpg.d/` is not the standard or correct default directory for GPG configuration and keyrings.