In the US, Which of the Following Questions Is Most Likely to Likely

In the U.S., which of the following questions is most likely to be considered illegal in interviews when hiring?

A) "Susan, why should we hire you?"
B) "Susan, could you describe how you resolved any conflict, personal or professional, in your last organization?"
C) "Susan, you've been married for four years. So, when are you planning to have children?"
D) "Susan, what contribution would you make to our organization if given the job?"