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: [header] How to bend rebar [title] Understand the structural issues possible with manually-bent rebar and know how to avoid them. [step] When you bend metal, you naturally weaken it. When done correctly, however, you can minimize damage and still get the shape you need to complete the project. <sep> (A) [substeps] Badly bent rebar acts as a buffer for the metal particles of the laser beam. The piece of rebar you are bending dissolves when squeezed into contact. (B) This effect is part of the re-bend method. The process is a little different than rebending a rubber band, but the difference is that you bend it in half by simply opening up a v on each end. (C) Because of this, it's important for you to know how to modify the shape you want the rebar to be. If you have a badly bent rebar, you'll likely create grooves in the rebar that introduce excess material. (D) Keep the following in mind as you work : [substeps] Always note the grade and size of the bar you're bending, checking against the equipment you're using to ensure it works. Check with your project engineer to ensure your bends meet the minimal internal bend diameter.
Example Output: D

Example Input: [header] How to become an endocrinologist [title] Obtain a bachelor's degree in a science-related major. [step] Though you could choose any major you want, it's best to study something like physiology, biology, or social science. These majors will help you build the prerequisite skills for medical school. <sep> (A) [substeps] If you are enjoying high school, they might teach you basic tests or techniques, like how to fight ethylene gas. Foreign nationals don't get their master's degree until they finish medical school. (B) [substeps] These degree levels will take some effort on your part, so keep an eye out for whatever college you want to attend. It's not always necessary to go to medical school if you're currently planning on med school. (C) [substeps] Enroll in or look for a program at an accredited medical school. Most states require endocrinology courses at high schools and universities. (D) In addition to studying science, you should also take courses in math, english, and the humanities. These courses can help prepare you for interacting with patients and writing reports.
Example Output: D

Example Input: A guy is sitting on a roof and talking. The guy holds up an orange tool. a silver ladder <sep> (A) is suspended from the roof. (B) is come from the roof. (C) is balanced on top of a roof and together the guys slide along the ladder. (D) is against the house.
Example Output:
D