Which one of the following is not the alien invasive species?

The correct answer is Option (2) → Rauwolfia

An alien invasive species is a species brought into a new area that spreads fast and harms the native species there.

(1) Eichhornia — An alien invasive species. The water hyacinth is an invasive weed.

(2) Rauwolfia — Not an alien invasive species. It is a medicinal plant, the source of the drug reserpine.

(3) Parthenium — An alien invasive species. Carrot grass is a harmful invasive weed.

(4) Clarias — An alien invasive species. The African catfish Clarias gariepinus was introduced for aquaculture and threatens the native catfishes.

NCERT Extract:
Loss of Biodiversity – “… You must be familiar with the environmental damage caused and threat posed to our native species by invasive weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eicchornia). The recent illegal introduction of the African catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous catfishes in our rivers.”
Biodiversity – “… The genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces.”