Red Data Book or IUCN Red List provides data on
B
Effect of red light or photosynthesis
Correct option is D. Threatened species
The species (including animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future are known as threatened species. The International Union for Conservation of Nature (IUCN) is the authority on threatened species, and it treats threatened species as a group of three categories, depending on the degree relative to which they are threatened. Those categories are Vulnerable species; Endangered species and Critically endangered species. As per the Red list of 2000, there are 11,096 threatened species.
So, the correct answer is 'Threatened species'.