a. Datura
b. Rauwolfia
c. Atropa
d. Papaver
Answer: b. Rauwolfia
Explanation: Reserpine is an indole alkaloid, antipsychotic, and antihypertensive drug used to control high blood pressure and relieve symptoms, although due to the development of better drugs for these purposes and because of its many side effects. , not widely used today.