Write the next sentence in the following story.

How to keep your dog or cat at its correct weight
Know the issues related to obesity.
The first step in combating pet obesity is to make sure your pet is not suffering from a medical illness that either contributes to obesity or is a complication from being overweight. In dogs and rarely in cats, hypothyroidism, or low thyroid hormone levels, can cause a pet to gain weight.

Choices:
a). Talk to your vet about weight loss solutions that will help your pet or cat lose weight. For example, you may use natural remedies such as chantix to control and suppress weight.;
b). Hypothyroidism can also cause a dog's hair to thin or fall out in patches. The dog may also become less playful and energetic.;
c). Self-awareness, chronic anorexia, and dental problems can lead to obesity and weight gain. Have your vet do a urinalysis to see what your pet usually eats.;
d). While there are no medical conditions in which a pet is overweight, genetic deficiencies in weight are fatal. Watch dog food intake to determine a cause.;. The answer should be
b).