Final answer:
Diane Ravitch suggests that standardized testing, diversity in curriculum, and social justice are beliefs interfering with educational reform; vocational education is NOT listed as such an obstacle. These views complement broader education reform discussions addressing organizational and incentive issues within schools.
Step-by-step explanation:
Diane Ravitch, an educational historian, posits that the comprehensive high school's lack of focus has been a detriment to successful educational reform. Among the beliefs that she argues have hampered this process, standardized testing (a), diversity in curriculum (b), and social justice (c) are often perceived as interfering factors. However, vocational education (d) is NOT one of the beliefs she identifies as an obstacle to successful educational reform. This aligns with broader conversations about education reform where proposals have been made to overcome organizational and management issues in schools, such as regular student testing, performance-based rewards for teachers, additional teacher training, school choice options, creation of new schools, and the implementation of student vouchers to enhance school success incentives.