Instructions: 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".
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.
Output:
A