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". 

Example Input: A bunch of men are inside a green colored gym. They are lobbing a tennis ball back and forth. they <sep> (A) are engaged in a game of tennis. (B) bounce the ball up and down on the trampoline as they go. (C) hit the ball up high into the air. (D) knock balls off the hoops into the spectators.
Example Output: A

Example Input: [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.
Example Output: A

Example Input: [header] How to prevent flip flops from hurting your feet [title] Wear them for short activities. [step] You can wear your flip flops for quick trips to the store, or to pick up your mail, and if you're meeting friends for a meal. As long as you won't be on your feet for a long time or doing something that risks injury, wearing flip flops is fine. <sep> (A) [title] Train your feet where you can slip, so that you don't end up with your wrist hurting. [step] Most people would assume someone else's wrist will be sore for an extended period of time. (B) [substeps] If you can hold them while leaving, try holding them while you're going to the store, too. Also, you can wear the flip flops while holding a book. (C) [title] Wear them to the beach or the pool. [step] Flip flops were really designed as a convenient and easy-to-wear shoe that you can take to the beach or the pool. (D) You just have to sit in them long enough to be comfortable. [title] Don't hesitate to take them off.
Example Output:
C