A, B, C, D and E are five members of a family. In this family there is a doctor, a teacher, a professor, a inspector and a businessman. A is the son of a professor. D is an unmarried lady. In the family there is a married couple in which B is inspector and husband of the professor. E is the brother of C and he is neither a teacher nor a businessman. Son of the married couple is not the teacher. There is no lady doctor in the family. The teacher is not married. Who is the teacher?