The correct answer is B. option A is for "Ellos" (they) option C is for "yo" (I) option D is for a third person but the conjugation works for "us." just try to translate the whole sentence: "The teacher gives us the books to the students." it does not make sense. However, if we use "B" the sentence is written properly. "La profesora les da los libros a los estudiantes" The teacher gives the books to the students.
