The meaning of this question is not completely clear. I see two possible ways to understand it. I will explore both possible meanings.
First, this question might mean “what characteristics could give a teacher an advantage if they had to work in a multicultural classroom?” In this case, there are two main characteristics. First, it would certainly be an advantage if the teacher has experienced multiple cultures. A teacher who has spent their whole life among people of different cultures will have an advantage over one with a more limited background. Second, a teacher with a flexible personality is likely to have an advantage over a more rigid one. A teacher who is more flexible will be more able to adapt to whatever happens in the multicultural classroom.
Second, this question might mean “what advantages do you gain by teaching in a multicultural classroom?” In this case, the answer is that you gain experience and you broaden your horizons. This will make you a better teacher because it will allow you to be more flexible and more able to adapt to different situations.