The correct answer is C. Nicad battery.
A Nicad battery is a type of rechargeable battery that uses nickel and cadmium as its active materials. It is a secondary battery, which means that it can be recharged after it has been discharged. Nicad batteries are commonly used in cordless electric knives, as they provide a good balance of power and capacity.
Zinc-carbon batteries are a type of primary battery that uses zinc and carbon as its active materials. They are not rechargeable, and they have a relatively low capacity. Zinc-carbon batteries are commonly used in small devices such as flashlights and remote controls.
Mercury-cell batteries are a type of primary battery that uses mercury as its active material. They are not rechargeable, and they have a relatively high capacity. Mercury-cell batteries are commonly used in hearing aids and watches.
Lead-acid batteries are a type of secondary battery that uses lead and lead oxide as its active materials. They are
commonly used in cars and other vehicles. Lead-acid batteries are not typically used in cordless electric knives, as they are heavy and have a relatively low capacity.None of the above is not a valid option.