Multi-choice problem: Continue writing the next sentence in this paragraph:

How to know when your dog is sick
Watch for excessive drooling or bad breath.
Excessive drooling or bad breath can be signs that your dog might need some teeth extracted. In order to prevent many dental problems, try to train your dog so that he allows you to brush his teeth.

A. Look for the following symptoms in your dog that might indicate a dental problem : Watch to see if your dog is eating less. Notice if your dog is sensitive to you touching his muzzle.; B. A dog with minimal gum tissue which contains all of the enamel necessary to promote healthy dental health, or shed gum to help prevent bad breath. Make sure that your dog is regularly eating and drinking water.; C. If you start to feel the effects of your dog's saliva or bad breath, it might be a sign of infection. If you notice any signs of illness during your dog's regular brushing, call your vet right away.; D. You can also check your dog's gums, allowing you to see which teeth you want to trim. You might even teach your dog to wear a sit-down collar if he turns his head, lip or muzzle up when you touch his teeth.;
A.