Definition: 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 manage your dog's bladder stones [title] Feed the dog food recommended by or prescribed by the vet. [step] This isn't a complete answer but it is a good start. [title] Be wary when your dog starts getting a lot of infections. <sep> (A) [step] These may be a sign that the bacteria causing the infections has become a substrate for the calcium and oxalate crystals. These tend to stick to and snowball into sizable stones. (B) [step] On the other hand, do not be alarmed if an infection develops. As something that is rare, but irritating, it does not cause an outbreak and the vet will not diagnose it. (C) [step] About 30% to 60% of dogs with tumors develop these infections and rarely become fatal. Tumors can be difficult to treat, but severity is usually life-threatening. (D) [step] Over time, fleas and ticks can cause bladder stones. As soon as your dog stops and changes his habits, get him vaccinated.
Output:
A