The IUCN Red List is a catalogue of --

Species threatened with risk of extinction

The correct answer is Option (1) → Species threatened with risk of extinction

The IUCN Red List records plant and animal species and assesses their conservation status, highlighting those that are endangered, vulnerable or critically endangered.

Established in 1964, the International Union for Conservation of Nature (IUCN) "Red List" of Threatened Species has evolved to become the world's most comprehensive information source on the global conservation status of animal, fungus, and plant species.