> they/them
For a non-binary person in the context of the question, ‘they/them’ is the best answer.
This is because the term ‘non-binary’ itself is someone whose gender identity isn’t exclusively male or female. Some non-binary people experience their gender as both male and female, and others experience their gender as neither male nor female.
But, in real life, it would be best to ask the person what their preferred pronouns are.
