Wood pulp is used for making

Wood pulp is used for making paper.

Wood pulp is treated chemically to convert to fibres. They are also bleached to remove or lighten the colour. The liquid is spread on a screen and pressed such that water is removed from it. Furthermore, the screen is subjected to drying to evaporate the remaining water, and what is obtained is a raw form of paper which can be cut in various sizes and used accordingly.

Timber is the wood used in carpentry or for construction. Plywood is used in construction to make floors, ceilings, etc. Firewood is dry wood used as fuel. All of these are directly made from wood and not wood pulp.

Hence, option B is correct.