Introduction:
West Bengal is a state located in the eastern region of India. It is known for its rich biodiversity and is home to several national parks and wildlife sanctuaries. One of the most famous and important wildlife reserves in West Bengal is the Sundarbans National Park.

Sundarbans National Park:
- The Sundarbans National Park is located in the Sundarbans delta in the Indian state of West Bengal.
- It is one of the largest mangrove forests in the world and is a UNESCO World Heritage Site.
- The park is spread over an area of about 10,000 square kilometers, with a significant portion falling within West Bengal.
- It is situated at the mouth of the Ganges and is formed by the confluence of the Ganges, Brahmaputra, and Meghna rivers in the Bay of Bengal.
- The Sundarbans is known for its unique ecosystem, which consists of mangrove forests, tidal rivers, and numerous small islands.
- It is home to a wide variety of flora and fauna, including the Royal Bengal Tiger, which is the most famous and iconic resident of the park.
- Other notable wildlife species found in the Sundarbans include estuarine crocodiles, Indian python, spotted deer, wild boar, and various species of birds and reptiles.
- The Sundarbans National Park is not only important for its biodiversity but also plays a crucial role in maintaining the ecological balance of the region.

Other Options:
- Corbett National Park: Corbett National Park is located in the state of Uttarakhand, not in West Bengal. It is one of the oldest national parks in India and is known for its population of Bengal tigers.
- Sariska Wildlife Sanctuary: Sariska Wildlife Sanctuary is located in the state of Rajasthan, not in West Bengal. It is a popular tourist destination and is home to various wildlife species, including tigers, leopards, and deer.
- Bandhavgarh National Park: Bandhavgarh National Park is located in the state of Madhya Pradesh, not in West Bengal. It is known for its high density of Royal Bengal Tigers and is considered one of the best places in India to spot these majestic animals.

Conclusion:
In conclusion, the Sundarbans National Park is located in West Bengal. It is a unique and important wildlife reserve known for its mangrove forests and diverse range of flora and fauna. The park is of great ecological significance and is a major tourist attraction in the region.