A safety precaution designed to prolong the life of a lead acid accumulator is

A.

By topping up the cells with concentrated acid

B.

The use of naked flame when charging the battery

C.

Keeping the specific gravity of the electrolyte within specified range

D.

By connecting wires to the terminals directly when testing the level of charging

Correct answer is C

- Topping is done with distilled water
- Naked flame should be avoided when charging the battery
- Direct connection of wires to the terminals should be avoided.