My mother is ... School teacher A) a B) the C)

 My mother is a school teacher.  A) a .

Моя мама школьная учительница.

My mother is not  a school teacher.

Is my mother a school teacher? (General question).

Who is a school teacher? (Special question).

What is my mother? (Special question).

Is my mother or is his mother a school teacher? (Alternative question).

Is my mother a school or a college teacher? (Alternative question).

Is my mother a school teacher or a doctor? (Alternative question).

My mother is a school teacher, is not she? (Disjunctive question).