The correct answer is A. British.
The Portuguese were the first Europeans to arrive in India in 1498, but they did not establish a permanent presence in Bihar until the 17th century. The Dutch arrived in India in the early 17th century, but they also did not establish a permanent presence in Bihar. The Spanish arrived in India in the late 16th century, but they never had any significant presence in Bihar.
The British East India Company established a trading post in Patna in 1612. This was the beginning of British rule in Bihar. The British gradually extended their control over Bihar, and by the end of the 18th century, they had complete control of the region.
The British ruled Bihar for over 200 years. During this time, they made significant contributions to the development of the region. They built roads, railways, and canals. They also established schools, hospitals, and other public institutions.
The British left India in 1947. After independence, Bihar became a state of the Republic of India.