The correct answer is "oshisan, oshi-san". In Japanese, "oshisan" and "oshi-san" both refer to a medical doctor. The term "oshi-san" is a polite and respectful way of addressing a doctor, while "oshisan" is a more casual and informal term. The use of both variations in the answer suggests that either form would be acceptable when referring to a doctor in a polite and respectful manner.