The correct answer is option 'D', The Deccan.

Introduction:
During the 8th century, the control of Bengal passed from the Palas to a new dynasty called the Senas. The Senas originated from the region of the Deccan, which is located in central India. This transition of power marked an important period in the history of Bengal.

The Senas:
The Sena dynasty was founded by Samantasena, who was originally a vassal of the Pala dynasty. He rose to power in Bengal and established the Sena dynasty in the 11th century. The Senas ruled over Bengal for about a century, from the 11th to the 12th century.

Origin of the Senas:
The exact origin of the Senas is not well-documented, but it is believed that they originated from the region of the Deccan. The Deccan is a large plateau located in central India, which includes parts of present-day Maharashtra, Karnataka, and Telangana. The Senas were likely a warrior clan who migrated from the Deccan to Bengal.

Sena Rule in Bengal:
Under the rule of the Senas, Bengal witnessed significant political and cultural changes. The Senas strengthened the administrative and military systems of Bengal and expanded their influence over neighboring regions. They also patronized art, literature, and architecture, contributing to the development of a distinct Bengali cultural identity.

Legacy of the Senas:
The Sena dynasty played a crucial role in shaping the history of Bengal. Their rule laid the foundation for the subsequent political developments in the region. After the decline of the Senas, Bengal came under the control of various dynasties, including the Muslim rulers during the medieval period.

Conclusion:
In conclusion, the Senas, who originated from the Deccan region in central India, took control of Bengal from the Palas. Their rule marked an important period in the history of Bengal and contributed to the political, cultural, and architectural development of the region.