The Bash shell can be configured by various files that affect its behavior, such as setting environment variables, aliases, functions, options, and prompts. Some of these files are global, meaning they apply to all users of the system, and some are local, meaning they apply to individual users. The global files are usually located in the /etc directory, while the local files are usually located in the user's home directory, which is denoted by the tilde (~) symbol1.
The local files that affect the Bash shell are:
* ~/.bash_profile: This file is executed when a user logs in to the system. It is used to set up the user's environment, such as the PATH, the default editor, the umask, and other variables. It can also run commands that are needed only once per login session, such as ssh-agent or fortune. This file can also source other files, such as ~/.bashrc, to inherit their settings12.
* ~/.bashrc: This file is executed when a user starts a new interactive shell, such as opening a terminal window or running a script with the shebang #!/bin/bash. It is used to set up the user's shell preferences, such as aliases, functions, options, and prompts. It can also source other files, such as /etc/bashrc, to inherit their settings12.
* ~/.bash_logout: This file is executed when a user logs out of the system. It is used to perform any cleanup tasks, such as clearing the screen, deleting temporary files, or printing a farewell message1.
The other files listed in the question are not valid Bash configuration files and do not affect the behavior of the shell. Therefore, the correct answer is B. ~/.bashrc and E. ~/.bash_profile.
References: 1: Bash Shell Configuration Files - Land of Linux 2: Bash Startup Files - GNU Project

values

The set command is used to display or modify the shell variables and functions in the current shell. When used without any arguments, it prints the names and values of all shell variables, including environment variables and user-defined variables, in alphabetical order. The output also includes the shell options and the positional parameters. The set command can be used in any POSIX-compliant shell, such as bash, zsh, ksh, etc123.
The other options are not correct because:
env is used to print or modify the environment variables, not the shell variables. It does not show the user-defined variables or the shell options. It can also be used to run a command in a modified environment45.
env -a is an invalid option for the env command. The -a option is not supported by the env command in any standard or common implementation45.
echo $ENV is used to print the value of the environment variable ENV, not the list of all shell variables. The ENV variable is usually set to the name of a file that contains commands or aliases to be executed by the shell. It is mainly used by the ksh and some versions of bash .

etcskel
Explanation:
The /etc/skel directory contains files and directories that are used as a template for creating a new user's home directory. The useradd command uses the -m (or --create-home) option to create the user home directory as /home/username and copy the files from /etc/skel to it. The files in /etc/skel are typically initialization files such as .bashrc, .profile, and .bash_logout that set the user's environment variables, aliases, and other preferences. The system administrator can customize the /etc/skel directory to provide a consistent and convenient initial setup for new users. Reference:
https://www.howtouselinux.com/post/create-new-user-with-home-directory-in-linux
https://linuxize.com/post/how-to-create-users-in-linux-using-the-useradd-command/