The Gradual Decline in the Quality of Teachers Is the Result

The gradual decline in the quality of teachers is the result of

A) university and college education programs that place more emphasis on educational methodology (how to teach) rather than on substantive knowledge in their specialized fields.
B) changes in the jobs available to women, who once had fewer opportunities in the workplace other than teaching, nursing, or clerical work.
C) the elevated expectation for teachers.
D) All of these choices.