The famous botanical garden “Kew” is located in

The correct answer is England.

Explanation:
The Royal Botanic Gardens, Kew, commonly known as Kew Gardens, is a world-famous botanical garden located in Richmond upon Thames in southwest London, England.
Here are some key facts about this historic institution:
1. History: Established in 1840 from the exotic garden at Kew Park, its history dates back to the 18th century as a royal estate.
2. UNESCO World Heritage Site: It was designated as a UNESCO World Heritage Site in 2003 in recognition of its unique history, landscape design, and scientific significance.
3. Scientific Importance: Kew houses one of the largest and most comprehensive botanical and mycological collections in the world, containing millions of preserved plant and fungal specimens, living plants, and a vast library.

Analysis of other options:
- Lucknow: Located in India, Lucknow is home to the National Botanical Research Institute (CSIR-NBRI), not Kew.
- Howrah: Located in West Bengal, India, Howrah is famous for the Acharya Jagadish Chandra Bose Indian Botanic Garden (home of the Great Banyan Tree).
- America: While the United States has many renowned botanical gardens (such as the New York Botanical Garden), Kew is strictly located in the United Kingdom (England).