Which Bash

[Charlse Darwin]

$ echo $BASH_VERSION
2.05b.0(1)-release
$ bash --version
GNU bash, version 3.2.33(1)-release (powerpc-apple-darwin8.11.0)
Copyright (C) 2007 Free Software Foundation, Inc.
$ which bash
/opt/local/bin/bash
$
# Which bash is being used by the system; 3.2.33(1)-release or 2.05b.0 
(1)-release?