The term "mosaic frame" when applied to Indian Secularism highlights the unique nature of secularism in India. A mosaic is composed of many distinct pieces that together form a complete picture, with each piece retaining its individual character. (a) describes the freedom and dignity of religions/ languages, which is a necessary condition for a mosaic to form, but not the core concept of the mosaic itself. (b) "Because in it all groups without losing their identity become a part of the composite culture" directly aligns with the mosaic analogy. It signifies that various religious, linguistic, and cultural groups maintain their distinct identities while co-existing and contributing to the larger composite culture of India. This is often contrasted with the Western concept of secularism which might involve strict separation of state and religion or assimilation. (c) describes a consequence (uniting common masses), not the reason for the analogy. (d) describes a feature of Indian secularism (no state religion), but not the specific aspect captured by the "mosaic" analogy. Therefore, statement (b) best explains why Indian Secularism is referred to as a mosaic frame.