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". 

[header] How to solo travel to vienna [title] Plan to stay in a hostel. [step] When traveling alone, it's always a good idea to stay at a hostel. Not only are hostels generally cheaper than hotels, this will help you meet people during your travels. <sep> (A) Taking advantage of free accommodations can help you pass the time and save money. [title] Plan initial backpackers getting used to the cities and customs of vienna on the flat travelling budget. (B) While there are many events you may enjoy alone, vienna has a booming nightlife. On occasion, you may want company for a night out, so a hostel is a good option for this. (C) It will also offer a safe, modern way to escape from the nightlife. An hostel is also a good place to set your budget on a day-to-day basis as you decide if you want to stay alone. (D) Search online for hostels near you if you want to take a trip somewhere you've never been, and plan to stick to the hostel's offerings. [substeps] The best traveling companions who are available in these places will be people who seem friendly, adventurous, and easily reunited from their long life.
B

[header] How to teach your dog to speak [title] Choose your reward. [step] Pick something your dog really loves; the better the reward, the easier it will be to teach your dog. If your dog loves to play, you can try using her favorite toy and playing with her when she barks. <sep> (A) In some cases, you can train your dog to bark through verbal praise. [substeps] Figure out your dog's reward based on cultural context. (B) Point out what your dog likes to play with and put a look on the chart indicating what she wants to learn. [title] Tell your dog to " sit ". (C) Most people, however, will find that treats are the most effective way to teach a dog. The best treats will be ones your dog loves, and which are also easy to carry, easy to break into pieces, and healthy. (D) If her bark is off-putting, encourage her to try other tricks, to avoid barking. [substeps] If you provide a toy or two, this will be enough to train your dog to try the reward.
C

[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.

A

