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 know if your dental fillings need replacing [title] Watch for tooth sensitivity. [step] If you have fillings that need replacement, you'll likely feel it first. Paying attention to the physical symptoms of old or decaying fillings can let you know if it's time to have your dentist replace them. <sep> (A) One sign that your fillings may need replacing is if you have tooth sensitivity to temperature, sweets, or pressure. [substeps] Pay attention when you bite into any cold, hot, or sweet foods. (B) Teeth sensitivity occurs when gums become severely stained with white blood. These white discolorations are mainly due to gum disease, but most commonly introduce a white blood cell colony to the side of your mouth. (C) Once your doctor notices an increase in tooth sensitivity, he or she can return you to the dentist. [substeps] Are your teeth hurt or moist? Severe tooth pain, cramping, sensitivity, or tingling are all signs that they need replacement. (D) [substeps] Bad tooth sensitivity is usually not a problem until it gets worse and you start to feel pain. You may experience sensitivity at night and bad teeth at the same time.
Example Output: A

Example Input: [header] How to buy a blackhead remover [title] Learn your options. [step] You should not squeeze or pick at blackhead, as this can lead to infection or scarring. However, you can remove pesky or unsightly blackheads with several different types of products that may not necessarily irritate your skin or require treating it with chemicals. <sep> (A) Learning your different options can help you identify the best product for your specific blackhead removal needs. Products that can remove blackheads include : [substeps] Extractor tools pore strips clay masks topical creams [title] Identify the best remover for your skin type. (B) For example, cleansing a burnt face can peel pores, like blackheads, and subtly remove blackheads. Deep pore pimples, which are a common factor for blackheads, are not tended to dry out. (C) [substeps] Avocado, keratin, and brewer's yeast all work well in reducing the inflammation and scarring of blackheads. [title] Pick a chemical neutralizer for stubborn blackheads. (D) Some of the well known brands that are known for their blackheads include tootane, steam, huawba, and celandine. As noted above, these products are more environmentally friendly than other skincare products, especially for those kids.
Example Output: A

Example Input: [header] How to remove watch band links [title] Measure the watch band. [step] Before you set about removing any watch links, it is necessary to measure your watch band so you know exactly how many links you will need to remove. To do this : [substeps] Position the watch on your wrist exactly the way you intend to wear it. <sep> (A) If you want it to look more comfortable and easy to take off, start by measuring the distance from the watch band to one of the holes on the side of your wrist. You will need to measure halfway up your wrist. (B) When you are satisfied with the way it is positioned, turn your wrist over so that the watch band clasp side is facing up. With the watch band on your wrist, gather the slack in the band and hold the links together to simulate them being removed. (C) On a regular watch band, it will just slide off without you opening your eyes. Use a tape measure to measure the distance between the top of the band and the back of your watch band. (D) Place one end of a tape measure around the neck of the watch and measure the distance between the neck and the bottom. You will find this distance on either side of the watch band.
Example Output:
B