Q: In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.
Sentence1: Opal was pregnant and her doctor had some concerns. Sentence2: During an ultrasound she had seen markers for down syndrome. Sentence3: They needed to test the baby but the process was dangerous. Sentence4: Opal decided not to risk it because she didn't mind either way. Sentence5: Luckily her baby came out perfectly healthy in the end.
A:
Opal, Her doctor