The correct answer is: D. Patna
Sanjay Gandhi Botanical Garden is located in Patna, the capital of Bihar. It is one of the largest botanical gardens in India, covering an area of over 1000 acres. The garden was established in 1969 and is named after Sanjay Gandhi, the son of Indira Gandhi, the former Prime Minister of India.
The garden is home to a variety of plants, including trees, shrubs, herbs, and flowers. It also has a number of attractions, such as a lake, a zoo, and a museum. The garden is a popular tourist destination and is also a popular spot for picnics and other outdoor activities.
The other options are incorrect because:
- Darbhanga is a city in the Mithila region of Bihar.
- Bhojpur is a district in the southern part of Bihar.
- Kaimur is a district in the eastern part of Bihar.