The incorrect statement is option 'A' - "The Bhakti movement greatly enhanced Hindu-Muslim unity."

Explanation:

1. Overview of the Bhakti Movement:
The Bhakti movement was a socio-religious movement that originated in medieval India, particularly between the 14th and 17th centuries. It emphasized personal devotion (bhakti) to a chosen deity or god, and sought to establish a direct and intimate relationship between the individual and the divine.

2. Hindu-Muslim Unity and the Bhakti Movement:
While the Bhakti movement did contribute to religious and cultural transformations in India, it did not significantly enhance Hindu-Muslim unity. The movement predominantly focused on the revival and reform of Hinduism, and the popularization of devotional practices within the Hindu community.

3. Historical Context of the Bhakti Movement:
During the medieval period in India, there were often conflicts and tensions between Hindu and Muslim communities, particularly due to the establishment of Muslim rule by various dynasties. The Bhakti movement emerged as a response to these changing social, cultural, and political dynamics.

4. Emphasis on Bhakti in Hinduism:
The Bhakti movement emphasized the importance of personal devotion and love towards a chosen deity, such as Vishnu, Shiva, or the Goddess. It aimed to democratize religious practices by promoting the idea that devotion and sincere belief were more important than caste or social status.

5. Influence on Vernacular Literature:
One of the significant contributions of the Bhakti movement was the enrichment of vernacular literature. Bhakti saints composed devotional poetry and songs in regional languages, making religious literature accessible to the masses. This led to the development of regional literature in languages such as Hindi, Tamil, Kannada, Bengali, etc.

6. Popularization of Devotional Music:
The Bhakti movement also played a crucial role in popularizing devotional music as a means of expressing religious devotion. Bhajans, kirtans, and other forms of devotional songs became an integral part of the movement, enabling people to connect with their chosen deities through music and singing.

In conclusion, though the Bhakti movement enriched vernacular literature and popularized devotional music, it did not greatly enhance Hindu-Muslim unity. The movement primarily focused on the revival and reform of Hinduism, and its impact was largely limited to the Hindu community.