Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to feed an older dog with heart disease [title] Talk to your vet. [step] After your vet identifies symptoms of heart disease in your older dog, they should recommend treatment options, including how to best feed your dog. Listen closely to your vet's advice and follow it closely.

Ending1: [substeps] Depending on the severity of your pet's heart disease, your vet might prescribe a regular diet of commercial dog food or a more limited diet of prescription dog food. Ask your vet questions if anything is unclear. Ending2: Common treatment options include : [substeps] Exposing your older dog to natural light. Developing a treatment plan for your older dog. Ending3: Depending on the severity of the disease, your vet may recommend medications or surgery, as well as alternative treatments. The vet may also recommend food for immediate care. Ending4: Not everyone experiences heart disease at the same time, and it is often difficult to pinpoint it early on. Here are some common symptoms and how they affect the care your vet gives you : [substeps] Extreme pain.

Answer format: ending1/ending2/ending3/ending4