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".

Ex Input:
The doctor uses a brush to scrub nails and hands. A doctor washes their hands in a large stainless steel sink with hand soap multiple times. the doctor <sep> (A) uses the brush to rub a suture needle into his palms. (B) uses a towel to clean on the sink. (C) uses a small brush to wipe several areas on the body of the sink and change water for the other areas. (D) completely rinses their hands then clasps together and walks out of the room without touching anything.

Ex Output:
D

Ex Input:
[header] How to clean a vornado fan [title] Clean out dust in the outer grills using a vacuum cleaner brush. [step] You can use a brush attachment on a vacuum cleaner to clean out all of the dust from the outer grills. Make sure the fan is unplugged before vacuuming. <sep> (A) [title] Place a cleaning rod in each section of the fan and squirt some cleaning fluid through each rod. [step] Avoid getting any grease in the vents or rest tray. (B) Some of the cleaner should be removed from the outside if you use a cloth and brush as cleaning instructions are laid out in the manual. [substeps] Avoid cleaning the outer grills with dust because it can detach some of the insulation and contribute to the fan's cooling. (C) Wipe down the inside of the cover every few minutes so you can put the fan back together. [substeps] For maximum efficiency, you should wash your vornado fan at least once a month, which is right after each dry run. (D) Go slowly when vacuuming to ensure you clean out as much dust as possible. [substeps] This will only clean the outer part of the fan, not the inside blades.

Ex Output:
D

Ex Input:
[header] How to dissolve salt in water [title] Choose a salt. [step] There are many different salts available, and they all have different properties. The amount of epsom salt (mgso) that you can dissolve into a given amount of water at a given temperature will differ from the amount of table salt (nacl) that you can dissolve into the same water. <sep> (A) [substeps] They are either very high or very low salt. If you want a higher, more valuable salt, opt for some which will replace or exceed the normal low salt content. (B) The coating of salt is usually smaller but in density, and ranges in mass. [substeps] Mgsos are the spiralizers used to dissolve salt, but they do not harden as readily. (C) [substeps] You can find sea salt at marine supply stores, farmer's markets, or health food stores. Salt behaves differently in different levels of water than table salt. (D) [substeps] If you are trying to understand the dissolution process in general, you should stick with using table salt since the particles are smaller and will therefore dissolve easier. If you need to study the properties of a specific salt, use that salt.

Ex Output:
D