The correct answer is A. 4% to 6%.
Moisture content is the amount of water in a material expressed as a percentage of the dry weight of the material. Well-seasoned timber has a moisture content of 4% to 6%. This means that for every 100 grams of dry timber, there are 4 to 6 grams of water.
Timber that is not well-seasoned will contain more water. This can lead to problems such as warping, cracking, and decay. It is important to season timber properly before using it in construction or other applications.
Option B, 10% to 12%, is too high for well-seasoned timber. Option C, 15% to 20%, is even higher and is not acceptable for most applications. Option D, 100%, is the maximum moisture content that timber can have without rotting.