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 caulk walls [title] Clean the wall. [step] Caulk should never go on a dirty surface. Wipe down the wall with a dry cloth to remove dust. <sep> (A) Also use a brush to vacuum the surface. Don't use a brush on a dirty surface. (B) Then let the caulk dry and smooth out any uneven surfaces. Use a knife to cut a 2 inch (5.1 cm) square at the edge of the wall. (C) Next, caulk around the entire wall with a rag. A putty knife or a mop may work, too. (D) Wash with an all-purpose cleaner to remove grease and dirt. Rubbing alcohol and a wire brush will remove stubborn stains.
Output:
D