The correct answer to this question is B. It absorbs voltage spikes. Lead acid batteries have few advantages. For one, they are heavy and large. Secondly, they include a high number of toxic material, which requires proper recycling.
Lastly, they are dangerous to handle for they contain lead and acid. NiCad batteries have more advantages for they have longer battery life and can work in higher temperature ranges, without any loss performance. Compared to other cells, they have a low discharge rate, which is why they are useful in medical equipment and lighting systems. If they are completely discharged, unlike other batteries, they won't be damaged.