I know it doesn't sound right but I'm working on some English exams and one of the questions was this one. Maybe it's a mistake!
This question is gibberish; any teacher who uses it to teach English should be fired.
However, if I had to make a choice, as you do, I would choose (d) "He's a teacher." My reasoning is that "what" may be used to refer to a job title or category in common speech.
Dear all,
What could the answer be to the question: What's that man?
a. He's my brother.
b. It's an old man.
c. Yes, it's that man.
d. He's a teacher.
Thanks!
It reminds me of Hippy speech, or local Newcastle and Northern England, where people, men or women are referred to as "man"
So it could be a question put to someone..
"What's that, Man?".