The correct answer is C) Very short and frequent running and idle periods for the potable water pump. In a waterlogged hydro-pneumatic header tank, the compressed air cushion has been lost, causing the tank to become waterlogged. This leads to very short and frequent running and idle periods for the potable water pump. As the pump is activated, the water is quickly pumped out, causing the pump to shut off. However, without the air cushion, the water quickly refills the tank, triggering the pump to start again, resulting in this short, frequent cycling. The other options are incorrect because A) the pump would still start with demand, B) the pump would not have extremely long run times, and D) the pump would still stop when there is zero demand, just with very short cycles in between.