How can you reduce internal resistance of a lead acid battery?
A) Using strips of wood or celluloid as separators between electrodes. 
B) Using grids of hard lead-antimony alloy.
C) Using a specific manner of assembly of electrodes of electrodes with wood or celluloid separators in between.
D) Both option A and B.

Hint: As we know that the internal resistance is inversely related to the area of the electrodes which are dipped in the electrolyte. It is also inversely related to the temperature as well as the concentration of the electrolyte. Separators act as insulating pieces between the different plates.

Complete solution:
> As we know that the Lead acid battery chiefly consists of plates which act as actual electrodes and these are Sponge lead and Lead Peroxide. Also, the Negative electrode is made of spongy or porous lead and positive electrodes consist of lead oxide. The electrolytic solution in which these electrodes are dipped in is mainly of sulphuric acid and water.
> Plates will usually be plante or feature types. The feature type plate a grid of antimony-lead alloy is used with the lead peroxide. These grids help in reducing internal resistance due to their nature of electrodes. Separators are used as insulators between the different plates.
> Separators are usually made of either celluloid, specially treated wood, rubber fabric, the most commonly used separator is wood as it is the cheapest of all separators.
> So, using strips of wood or celluloid as separators between electrodes and using grids of hard lead-antimony alloy both helps in reducing internal resistance of a lead acid battery.

Therefore, the correct option is (D).

Note: Remember that the materials which are used for separators are generally celluloid which is treated with the wood and thereby making it a cheap separator which usually provides the internal resistance to the lead acid battery.