You will be given a definition of a task first, then some input of the task.
In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

[header] How to inspect a fireplace chimney [title] Remove the ashes and debris from the fire box. [step] Brush the sides and bottom with a stiff broom or chimney brush. Vacuum out the loosened ashes and if possible remove the andirons. <sep> (A) You may want to add a layer of sand or weld dust at this stage. Dry off the contents of the fire box evenly with a damp, paper towel and clean away any remaining dirt, soot or debris. (B) You can sometimes find the fire box by beneath the fireplace fireplace grate. Be sure you use a ladder to access the top. (C) [substeps] If you are working with flammable materials, such as wood, furniture, or stones, vacuum them away first to ensure they don't get into the fireplace. If working with furniture or stone, be sure to sweep for particles such as sawdust and soot. (D) [title] Open the screen and glass doors (if so equipped) as wide as possible, and place a large piece of cardboard or a drop cloth in the firebox. [step] Lay on your back and slide into the box as far as you need to so that you can shine a flashlight up the flue.
Output:
D