Answer:
c. President Franklin Roosevelt encouraged universal high school attendance.
Step-by-step explanation:
One of the factors that made adolescence a defined stage of life was the promotion of high school attendance. In the past, some people received secondary education and even higher education to become professionals. However, this was not universal. Between 1910 and 1940, changes were introduced to the American education system. This made high schools more common, easier to graduate from, and free. The changes led to a rise in school attendance. Adolescence in the United States was thereafter defined by the virtually universal experience of high school.