Absolutely 'C', no question about it. Especially since this is essentially a runway stop bar.
We have an Alpha 1, 2 & 3 as well. I suspect there might be quite a few about.
At least the failure in this case is fail-safe. The fail-hard case is where the bar disappears and pilots think it's OK to proceed. Any UK system should give a back-indication to the controller as to the corrct status of the bar, even if there's been a control failure.
Cheers,
TheOddOne