The correct answer is option 'B' Bengal.

Explanation:
The British started the Dual System of Government in Bengal in India. This system was implemented by the British East India Company in the late 18th century.

Dual System of Government:
The Dual System of Government was a system in which the British exercised both indirect and direct control over the administration of Bengal. It was a combination of Indian rulers and British officials governing the region.

Lord Clive was the key figure in implementing this system. Under this system, the Nawab of Bengal was retained as the nominal ruler, while the British East India Company had significant control over the administration. The Nawab was responsible for collecting revenue and maintaining law and order, but he had to consult with and seek the approval of the British officials in important matters.

Reasons for implementing the Dual System of Government:
1. Economic exploitation: The British wanted to exploit the economic resources of Bengal, especially the rich agricultural lands and the prosperous trade in textiles. The Dual System allowed them to control and benefit from these resources.

2. Political control: The British wanted to establish their political control over Bengal. The Dual System provided a way to maintain indirect control through the Nawab while having British officials in key positions of power.

3. Divide and rule: By implementing the Dual System, the British could create divisions and rivalries among the Indian rulers, making it easier for them to maintain control and prevent any unified resistance against their rule.

Impact of the Dual System of Government:
1. Economic exploitation: The British East India Company gained significant economic benefits through the Dual System. They imposed heavy taxes on the Bengal economy and extracted resources for their own profit.

2. Weakening of Indian rulers: The Dual System weakened the power and authority of the Indian rulers, as they became dependent on the British for decision-making. This eventually led to the complete annexation of Bengal by the British.

3. Administrative reforms: The British introduced administrative reforms in Bengal under the Dual System. They established a bureaucracy and implemented British laws and regulations. This laid the foundation for the British colonial administration in India.

In conclusion, the British introduced the Dual System of Government in Bengal to exploit its economic resources, establish political control, and weaken the Indian rulers. This system had a significant impact on the region, leading to economic exploitation, administrative reforms, and the eventual annexation of Bengal by the British.