To teach school in most parts of the United States, one must have passed numerous college courses taught by the education department. Based on what the reading section said, economists are most likely to argue that these required courses:
raise the productivity of teachers and hence increase the pay they receive.
increase the demand for the services of teachers, and hence raise the pay they receive.
decrease the supply of teachers, and hence raise the pay they receive.
discourage people from becoming teachers, and thus lower the pay of teachers.