Final answer:
In a developing relationship, someone would be least likely to ask about their partner's relationship with their parents growing up.
Step-by-step explanation:
In the context of a developing relationship, a person would be least likely to ask about their partner's relationship with their parents growing up. This question delves into personal, potentially sensitive information that may not be appropriate to discuss early on in a relationship. It often takes time for individuals to feel comfortable sharing intimate details about their family relationships. In comparison, questions about major choice, getting along with roommates, and hobbies are more common and less personal topics that can help individuals get to know each other better.