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 relieve constipation after surgery [title] Use a stool softener. [step] One of the first medications to try if you're feeling constipated is a stool softener. These are easy to find over-the-counter and can help get you back on track. <sep> (A) [substeps] The way that stool softeners work is that they draw water into your stool from your intestines. This makes your stool softer and easier to pass. (B) [title] Take 600ml of stool softener before a meal. [step] Most stool softeners kill the production of prostaglandins. (C) [substeps] One good option for relieving constipation at the time of surgery is a stool softener. While stool softeners do provide temporary relief from constipation, they are expensive and will often disappoint you. (D) These medications are named for their antioxidant properties, which help reduce diarrhea and keep your stools from becoming irritated. [substeps] Remember that: the next time you're using an over the counter stool softener treatment, be sure to follow the dosing instructions.
A

[header] How to exercise to prevent blood clots [title] Get up and move around. [step] Whether you're traveling by train, plane, or automobile, long-distance travel involves a lot of sitting. When you sit, you decrease circulation in your legs-especially if you sit with your legs crossed or with one foot under you. <sep> (A) If you are on a train or coach, the seat underneath you always feels flat, as if you are sitting. While there are good ways to stretch out your legs, there is not a lot a group of people can do. (B) This will help promote blood circulation to your feet. It will also keep you from rubbing your legs in an annoying manner-you can't promote blood flow when you're sitting on one leg. (C) [substeps] You can exercise while you drive or driving, although getting up and down on the exercise train can significantly improve circulation. You can also listen to music while you exercise, which will also help to prevent blood clots. (D) [substeps] If you're on a plane, try to get an aisle seat so you can get up and move around more easily. Ideally, you want to get up and stretch your legs or walk up and down the aisle once every hour or so.
D

[header] How to find a dog sitter or boarding kennel [title] Check online. [step] The easiest way to find a pet sitter is online. There are a number of professional dogsitting companies that provide searchable databases or maps that can help you locate a dog sitter near you. <sep> (A) Take advantage of these online resources to locate a pet sitter near you. [substeps] Petsitter.com, for instance, has a database at https: // petsitter.com/pet-sitters. (B) Some websites, such as wepet.com and petco, provide links to ad boxes for a variety of sites. [substeps] Also, look in the phone book and search " breeders of dog " or " dog parks. (C) Make sure you are on the right id before you begin searching. [title] Run a quick research through your dogs attention process to find a pet sitter that does not take your dog to the same places you are. (D) They may be able to point you in the right direction if you have any questions or are curious about a particular breeder or yard. [substeps] Most dog sitters and trainers will have a search tool up front, like petfinder, and then a key checklist from which to search, such as the classifieds.

A