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".
Q: [header] How to improve your sleeping position [title] Put a pillow between your legs. [step] Sleeping on one side of your body is known to be one of the most comfortable positions and one of the most common. To make this position more comfortable, try putting a pillow between your bent legs. <sep> (A) [substeps] If you don't have the support of a good bed, you may like sleeping on your back instead. [title] Pick a pillow with a natural weight. (B) [title] Determine if you're flat on your back. [step] Not only is it common for your tailbone to feel restricted by your pillow, but it also puts pressure on your joints. (C) You can find pillows in cushioned sleeping bags or in foam boxes. [substeps] Some studies have shown that sitting with your lower legs out keeps your heart rate up, which can reduce snoring. (D) Slide the pillow between your knees and keep the pillow in place as you lay down on your side. This can help to protect your lower back and take the strain off your neck as you sleep.
A:
D