Respuesta :
The answer is A.
It cannot be 'de la' since the teacher is male.
It cannot be 'des' since there is not more than one teacher.
It cannot be 'de l'' since the word 'professeur' does it start with a vowel.
It cannot be 'de la' since the teacher is male.
It cannot be 'des' since there is not more than one teacher.
It cannot be 'de l'' since the word 'professeur' does it start with a vowel.