By the Middle of the 20th Century, Aspiring Teachers Had

By the middle of the 20th century, aspiring teachers had to undergo a four-year degree program to qualify as teachers instead of the earlier practice of pursuing two-year schooling. This professional requirement

A) promised to increase autonomy in classrooms for teachers.
B) ensured that the salaries of teachers would be similar to those of other professions.
C) did not result in an increase in teacher autonomy in schools.
D) resulted in uniform learning outcomes for all students in a classroom.