Detailed Instructions: 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".
Q: [header] How to determine the sex of a guinea pig [title] Do not examine cavies who are younger than three weeks old. [step] Newborn cavies can be rejected by their mothers if they are handled by humans, as your smell will end up on their coats. Newborn cavies can also become easily distressed when away from their mothers, leading to a very difficult time trying to examine their genital area. <sep> (A) [substeps] Many baby guinea pigs can get cold quickly and may become too cold during the examination. If you feel you need to examine a baby guinea pig that is three weeks or younger, you should try to do it quickly and gently. (B) [substeps] Cavies should be taken to a veterinarian to be examined. They should be kept in a monogamous home. (C) [title] Check for signs of aggression when selecting a toy. [step] Cavies can become easily agitated whenever they're alone and need to be handled by a young adult, particularly when exercising. (D) [substeps] As with any food, do not contact a vet if you see an individual cakie sniffing in someone's area. [title] Ask for a rejection to determine the sex of a guinea pig.
A:
A