Q: 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 use an inversion table for back pain [title] Secure your inversion table on a flat surface. [step] Ensure that all the joints, straps and pivot points are correctly connected. Do this every time you use the table in order to avoid a serious accident. <sep> (A) [substeps] Stacking your work surface will make it easier to quickly locate and properly align your free elbow joints. [title] Put a piece of paper on a flat surface. (B) [substeps] Your table should not have a flap or other covering covering your inversion table. Any flap, especially if it is rolled up or screwed up, will prevent dust from entering it. (C) [title] Assess if your patients are suffering from back issues. [step] If the sufferer of back pain frequently has a problem in their back, try to fix the issue right away. (D) [substeps] Read your inversion table instructional manual thoroughly before attempting to use the table. It will support your body weight, so it is important that all the steps are done correctly.
A:
D