The Song Dynasty was unique for the Middle Ages because a person's social class could change.

This phenomenon, known as social mobility, was made possible by Confucianism-a belief system that emphasized social harmony and personal education. To implement these principles, the Song Dynasty introduced the Civil Service Exam, aiming to hire people for government positions based on people's ability rather than family wealth. This innovative approach meant that anyone, regardless of their social background, could become a scholar-official, one of the era's most respected and lucrative professions.
Despite this open opportunity, the majority of successful candidates in the Civil Service Exam still hailed from wealthy families. This trend emerged because rich individuals had the financial means and leisure time to hire tutors and dedicate themselves to studying. In contrast, peasant farmers hoping to take the exam lacked the luxury of hiring a tutor, forcing them to pursue a self-directed education. The challenging nature of the exam, coupled with the widespread desire to attain the esteemed position of scholar-official, resulted in a limited number of successful candidates.
Consequently, the majority of the population remained in their roles as peasant farmers.

Does this source seem to suggest that the Song Dynasty was a golden age? Identify one sentence from this source that supports your answer

No, this source does not suggest that the Song Dynasty was a golden age. One sentence from the source that supports this is "Consequently, the majority of the population remained in their roles as peasant farmers." This implies that the majority of the population did not experience the benefits and upward mobility that the Civil Service Exam and Confucianism aimed to provide.