A systems administrator downloads an application's source files, compiles the application, and installs it per the application's installation instructions. When trying to run the application, the…

Creating a symbolic link from the executable's location (`/opt/occmd/bin/occmd`) to a directory already in the system's PATH (such as `/usr/local/bin/`) allows the shell to find and execute the command by its name directly.

Modifying the `PATH` environment variable by adding `/opt/occmd/bin` to it ensures that the shell searches this directory when looking for commands, thus allowing `occmd` to be executed by name. This change is typically made persistent by adding it to `~/.bashrc`.

Moving the application to the home directory is not a standard practice for system-wide applications, and the symlink created would only be local.

This command attempts to create a shell script but uses incorrect syntax for executing and redirecting the output of `which occmd` and would not make `occmd` executable.

`/etc/bin/` is not a standard directory for executables; `/etc` is for configuration files.

While `chmod +x` is necessary to make a file executable, and `restorecon` handles SELinux contexts, these actions do not solve the 'command not found' error if the executable's directory is not in the system's PATH.