The correct answer is: D. Vertical wooden member.
A nogging is a short piece of wood that is used to fill in the space between studs in a wooden partition. It is typically installed perpendicular to the studs, and it helps to provide support and stability to the partition.
The other options are incorrect because they do not describe the function of a nogging. Option A, upper horizontal wooden member, is incorrect because a nogging is not typically installed horizontally. Option B, lower horizontal wooden member, is incorrect for the same reason. Option C, intermediate horizontal wooden member, is incorrect because a nogging is not typically installed at an intermediate height.
I hope this helps! Let me know if you have any other questions.