BEGIN { require module }
##</code><code>##

BEGIN {
  my $version = (($0 =~ /2(?:\.pl)?$/) ? '2' : '');
  require "LayerB${version}.pm";
}

##</code><code>##

BEGIN {
   # set $version based on $0
  require "LayerB${version}.pm";
  "LayerB${version}"->import(qw(A B C));
}