The correct answer is B. Lucknow (Uttar Pradesh).
The National Botanical Research Institute (NBRI) is a premier research institute in the field of botany in India. It is located in Lucknow, Uttar Pradesh. The institute was established in 1956 by the Indian Council of Agricultural Research (ICAR). It is one of the largest botanical research institutes in the world. The institute has a mandate to conduct research in all aspects of botany, including taxonomy, systematics, ecology, physiology, biochemistry, molecular biology, and biotechnology. It also has a mandate to train scientists and technicians in the field of botany. The institute has a well-equipped library and a herbarium with a collection of over 1 million specimens. The institute also has a number of laboratories and greenhouses. The institute publishes a number of scientific journals, including the Journal of the National Botanical Research Institute and the Indian Journal of Plant Physiology. The institute also organizes a number of scientific conferences and symposia.
The other options are incorrect. Option A is incorrect because the National Botanical Research Institute is not located in New Delhi. Option C is incorrect because the National Botanical Research Institute is not located in Chennai. Option D is incorrect because the National Botanical Research Institute is not located in Bangalore.