i would say (B) or (C) i live in Scotland and when the gas company came a few years back for theyre annual check on my boiler and pipes,they told me as its been installed a few years i must get the boiler to meter earthed myself.
On a new gas installation you would think the corgi registered gas fitter woudnt be able to sign of the job as complete without getting the earthing done.
Arto
November 2008