Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to diagnose canine anal sac problems [title] Locate your dog's anal sacs. [step] Look for two sacs on either side of your dog's anus, at the " twenty past eight " position on a clock face. The sacs should each be the size of a small grape and sit just underneath the skin.

Ending1: Look for one like this : [substeps] Between the scrotum and anus. Two sacs should sit right over the scrotum, above the sacs. Ending2: They should be about 0.05 centimetres (0.04 in) wide and 3 centimetres (0.91 in) long. [substeps] If your dog's sacs are not visible, check your dog's diapers frequently during the day. Ending3: [substeps] Your dog's anal sacs drain out onto his feces through small ducts. When your dog needs to toilet, the squeezing action forces a few drops of the smelly secretion out of the sacs and onto each bowel movement. Ending4: [substeps] You'll find one obviously to the rear of the anus. The two sacs should rotate a lot before you see one curling upwards.

Answer format: ending1/ending2/ending3/ending4