Step 1: Understanding the Concept:
Gene banks are repositories used for ex-situ conservation of plant genetic resources, maintaining them in the form of seeds, pollen, tissue cultures, or cryo-preserved cells.
Step 2: Detailed Explanation:
The National Plant Gene Bank of India is housed and managed at the ICAR-National Bureau of Plant Genetic Resources (NBPGR) in New Delhi.
It is one of the largest germplasm repositories in the world, maintaining hundreds of thousands of accessions of wild relatives and cultivars of diverse food, fiber, and horticultural crops.
Step 3: Final Answer:
The National Plant Gene Bank is located at ICAR-NBPGR, New Delhi, which corresponds to option (B).