The correct option is B Richest and most threatened reservoir of plant and animal life on earth.
A biodiversity hotspot is a biogeographic region, that is both a significant reservoir of biodiversity and is threatened with destruction. The term biodiversity hotspot specifically refers to 25 biologically rich areas around the world that have lost at least 70% of their original habitat. To qualify as a biodiversity hotspot on Myer's 2000 edition of the hotspot-map, a region must meet two strict criteria: it must contain at least 0.5% or 1,500 species of vascular plants as endemics, and it has to have lost at least 70% of its primary vegetation.