The mirror of the Society is:

In the sociological foundations of education, a school is described as a deliberately organized social institution that reflects, and helps reproduce, the values, culture, structure, and social roles of the wider society that establishes it. Because it recreates society's key relationships and transmits its culture to the next generation in a controlled, smaller setting, this idea is summarized in the classical teacher-education maxim that the school is the mirror of society, also phrased as society in miniature.

Applying this to the given options: among Playground, Community, Hospital, and School, it is School whose entire structure, curriculum, and social relationships are organized specifically to reproduce and pass on society's values and norms to children, which is exactly why it is called society's mirror.

• Playground: a space for recreation and physical activity among students; it does not itself function as an institution that reflects the wider society.

• Community: the broader social whole that is being reflected, not a distinct institution that does the reflecting.

• Hospital: a healthcare institution focused on treatment and medical care, unrelated to transmitting values or culture.

This matches the standard description of the school-society relationship found in teacher-education (B.Ed.) material on the sociological foundations of education, confirming School as the option that fits the description.