Final answer:
The word 'sedulous' in the context means 'diligent'. Klara was diligent in her studies, which is why she earned top scores. The concept of assigning students to classes based on ability is known as 'tracking'.
Step-by-step explanation:
The word sedulous, as used in the provided context, means being diligent in pursuit of a goal. Klara's sedulous commitment signifies her persistent and hardworking nature in her studies, which helped her achieve top scores. Therefore, the correct answer to the definition of 'sedulous' in the given sentence is diligent.
In the context of education, the assignment of students to specific education programs and classes based on test scores, previous grades, or perceived ability is called tracking. This process can often reinforce social inequalities, as exemplified in the passage about the student from a working-class home who, despite his willingness to succeed, faces numerous obstacles that hamper his academic progress.