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 avoid the stomach flu [title] Wash your hands often. [step] Wash your hands carefully with soap and water for at least 20 seconds. Always wash your hands after going to the washroom and before and after handling food and eating. <sep> (A) Washing your hands is important, since if the way you handle and eat is bad (germs, bacteria, etc. ), your best chance at preventing the flu is by keeping your hands clean. (B) Don't attempt to dry or clean your hands on something other than a business table. [title] Wear long pants (not utility pants to wear running shoes with). (C) [substeps] It's a good idea to wash your hands between-and as many times as you go to the bathroom. This will help prevent an episode of nausea in the future, as well as allow your body time to shut down its internal defenses to fight off food, germs, and viruses. (D) This will help to prevent the spread of germs. Germs on your hands can get into your eyes, ears, and nose and make you sick.
D

[header] How to get rid of migraines [title] Learn all you can about migraines. [step] Nobody knows exactly what causes migraines. A lot of research has gone into the exact cause of migraines, but with little success. <sep> (A) People who experience migraines regularly have been having regular consultations with doctors and they still don't know what is causing them. Anything you experience requires some much-needed research or hypnosis to rule out any medical issues or underlying conditions. (B) Migraines result from a lack of sensory focal points or groups. They occur in fewer than three brain groups. (C) Just finding out what causes them will give you some tips on dealing with them. [substeps] Most people develop migraines because they have no symptoms or aren't able to respond to stimuli. (D) It is generally agreed upon that the trigeminal nerve plays a role in migraine pain. The trigeminal nerve is a cranial nerve that facilitates a major pain pathway.
D

[header] How to stay underwater longer [title] Start a cardiovascular exercise routine. [step] The best way to increase the amount of time you can stay underwater is by increasing your cardiovascular ability. By committing to a cardio training exercise routine, you'll increase your body's ability to process and use oxygen. <sep> (A) [substeps] Do cardio 1 hour a day, even if you're not very active. Studies have shown that people who engage in cardio exercise their entire lives have lower cholesterol levels, which can help them go longer. (B) [substeps] Commit to running, powerwalking, using an elliptical, or another cardio activity. Exercise 3 to 5 times a week for at least 30 minutes. (C) This will help you to stay underwater longer, and even help prevent injury. You want to make sure that you've kept up your cardio pace as much as possible, without injury. (D) Take the following steps to start a cardiovascular workout regimen : [substeps] Start with a short run at a medium pace for 30 seconds. Running for 30 seconds is about the same as hopping 3 times--you increase speed in that time period.

B