Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to treat canine corneal ulcers [title] Watch for your dog rubbing his eye. [step] Since corneal ulcers are painful, the dog's eye will bother him because it hurts. This means your dog may rub his eye.

Ending1: Try to avoid scratching the area and see if he flinches at this pain. [title] Note any stimulus or behavior that makes your dog angry. Ending2: You may notice that he is rubbing his eye when in fact, the corneal ulcer is quite serious. As your dog moves closer, sees the ulcer as a sore eye, the ulcer may become infected. Ending3: Your dog might also squint with the affected eye and hold it partially closed. The discomfort and pain from the ulcer may also cause your dog's eye to water. Ending4: If you notice this recurring problem do not attempt to treat the ulcer. That will only irritate the tissues, which will reduce the pain.

Answer format: ending1/ending2/ending3/ending4