Find the statement which is necessarily true according to the given information:

The Asatra Vriksh is an evergreen tree that grows in the Nilgiris. The Asatra Vriksh has a fleshy, poisonous fruit. Recently, Purol, a substance found in the bark of the Asatra Vriksh, was discovered to be a promising new antidepressant drug.

A

Purol is poisonous when taken by healthy people.

B

Purol has cured people from various diseases.

C

People should not eat the fruit of Asatra Vriksh.

D

No treatment for depression was known till Purol was discovered.