Given the task definition and input, reply with output. In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

[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. <sep> (A) Look for one like this : [substeps] Between the scrotum and anus. Two sacs should sit right over the scrotum, above the sacs. (B) 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. (C) [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. (D) [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.
C