Endangered species are listed in

The correct answer is B) Red Data Book. Red Data Books are inventories of threatened plants and animals, each entry giving the species' conservation status. The IUCN publishes the global version, now called the IUCN Red List of Threatened Species, with categories such as Critically Endangered, Endangered and Vulnerable. India's Botanical Survey and Zoological Survey have also produced national and state Red Data Books.

• A) Dead Stock Book is wrong. It is an accounting or government-stores register of non-consumable assets, not a conservation document.
• C) Live Stock Book is wrong. It is a farm or livestock record of animals kept by owners, not a list of endangered wild species.
• D) None of the above is wrong because option B is correct.

The core concept is conservation status assessment, which links to the Wildlife Protection Act, 1972 schedules and the CITES appendices. For Mains, it fits questions on biodiversity loss, habitat conservation and India's obligations under the Convention on Biological Diversity.

Trap: Candidates confuse the Red Data Book with the Wildlife Protection Act schedules or CITES appendices. Those are legal protection lists. The Red Data Book is the status inventory.