Write the next sentence in the following story.

How to keep your dog entertained
Take a long, brisk walk first thing in the morning.
Before you leave for work, enjoy some time with your canine friend, and expel some of their energy by taking a walk together. You will both enjoy the exercise, and your dog will be able to have some time outside before they are cooped up inside the house all day.

A). Go for a walk only if your pet feels happy and relaxed in your presence. Just like humans, dogs' immune systems are highly susceptible to illness and aging.; B). A 20-minute walk daily is recommended for most breeds of dogs. Working dogs may need two 20-minute walks a day.; C). Walk your dog whenever you can because they will be happy to enjoy this way. Be sure to give them quick walk breaks and let them outside around the house.; D). One more option is to take your dog out. Make sure that neither one of you go to work and alone, or your dog could become anxious and cause a fire.;. The answer should be
B).