The answer is B. None of the others would make sense. Running on hard surfaces wouldn't reduce the likelihood of receiving injuries, and reducing the amount of walking wouldn't either. And limiting water intake would actually INCREASE chances of being hurt, as you could pass out. But wearing properly fitted shoes would mean that your feet are less likely to get hurt, by a blister, or them falling off while you run.
So the answer is B. Wear properly fitted running shoes.